In the aftermath of the Battle of Tukayyid, Comstar found itself in a bit of a bind. Fighting the clans had taken a massive toll on their stockpile of Star League era battlemechs and they needed to get new machines into production to make good their losses. One notable product of this rearmament program was the all new Raijin medium mech. Another was a not so entirely new light mech called the Nexus
Under the skin, the Nexus is based on the Jackrabbit, a machine designed for the Star League but with a tarnished reputation thanks to its exclusive use by RWR loyalists during the Amaris civil war. However, Skobel Mechworks had presumably kept their production tooling in mothballs for 300 years and it possessed a fundamentally decent chassis so Comstar just came up with a new variant, renamed the thing and started cranking them out in numbers.
The Nexus has a lot in common with the Jackrabbit structurally. Both machines weigh twenty five tons, use standard fusion engines and save weight instead through advanced construction materials. However, where the Jackrabbit has a light autocannon for long ranged combat, the Nexus opts instead for a shorter ranged, more powerful laser armament. Similarly, the Jackrabbit has mediocre mobility for a light mech and - whilst 114 km/h ground speed is by no means the fastest a machine this small can potentially go - the Nexus runs usefully faster than its forebear. The Nexus is also jump capable, although this is best used strictly for terrain handling as you can only jump 120 meters which isn’t nearly far enough to trouble most gunners.
The firepower is punchy for such a small mech. You have a left shoulder mounted medium laser for closing with the enemy and a medium pulse and small laser in each arm for knife fighting. That’s a lot of wallop for a twenty five tonner and the standard ten double heat sinks cover all the heat you can generate with ease, but to get the best out of it you need to close to 60 metres or less and that's a big problem - you see, with all this weight of engine and weapons the Nexus has only two tons of ferro-fibrous armour protecting its endo-steel bones. Some thought has been put into how best to deploy it but there's only so much you can do with this paltry level of protection. There is just enough armour to keep a small laser from damaging the structure if it strikes the arms, side torsos or head. The legs are fractionally better protected and the centre torso can, at least, survive a medium laser strike without breaching but if a Nexus falls on its back then it will inevitably damage its delicate internals. In lieu of heavy armour or exceptional speed for protection, the Nexus instead mounts an anti-missile system in its left torso and I can't honestly think of a worse use of mass for a mech of this type. Not only does it add an unwelcome explosive critical location to the thinly armoured left torso, it's also of very little help protecting the mech. I don't hate AMS in principle but the main threats to small, fast machines like the Nexus are pulse lasers and precision autocannon rounds against which an AMS achieves diddly squat. It's a complete waste of tonnage on a mech that desperately needs more armour and jump jets.
This puts a NXS1-A pilot in a bit of a bind, you have enough firepower to seriously harm something you decide to dance with but you have neither the armour nor manoeuvrability to survive such antics. In theory the standard engine should enable the Nexus to survive damage that would cripple most similar light mechs, but in practice there’s so little armour that a couple of hits from a heavy weapon will just blow you to bits regardless. As such it is probably best employed as a scout hunter - but only against older, slower machines like the classic bugs. I can see a machine like this having success in the densely crowded arenas of Solaris 7, but in open ground many contemporary Inner Sphere light mechs can easily show a clean pair of heels to a Nexus, and the ones that can't (and some of the ones that can, come to think of it) will have little difficulty piercing your armour. Taking one of these anywhere near the Clan front would require bona-fide balls of tungsten. In summary, not a well balanced machine.
Clearly the Nexus could not be allowed to remain in production as it was so in 3062 the Word of Blake came up with an improved Nexus, making a lot of sensible decisions in the process. The armament of the NXS1-B has been reduced to two ER medium lasers, one in each arm, and a single ER small in the centre torso. This means that while the mass devoted to weaponry is significantly cut back, at anything more than the shortest ranges the Nexus 1B is a much more dangerous machine. The weight saved is wisely spent on an additional jump jet - which makes the machine massively more elusive for such a meagre investment of tonnage - and twice the weight of armour. The Nexus 1B must still be careful not to fall on its back, but its frontal facings are much more resilient. The arms have twice the armour of the 1A, the side torsos can stand up to a large laser and the legs and centre torso can resist the assault of a PPC. I do wish there was a touch more armour on the head, however, as that same PPC can still blow it off with a single hit. Finally, in place of the AMS, the Nexus 1B mounts a C3i computer in its left torso. This changes the role of the machine from light strike and scout hunting to spotting for a level 2 of heavier machines and that is a role it performs well. The Nexus 1B can run and jump around firing it's lasers all day long without so much as a quiver on the heat scale and with the same standard engine as the 1A, this mech can suffer quite a lot of damage and still provide targeting data to the rest of its lance just so long as you don't lose the left torso.
Four years later the Word of Blake decided to revisit the Nexus again, utilising technologies unavailable to them in 3062. The subsequent redesign altered the machine’s appearance so radically they renamed it the Nexus II, but looks aside the NXS2-A has much in common with the NXS1-B. The mech is now powered by a 200 Light engine so the speed has been increased to 130 km/h without making an undue sacrifice in survivability. Jump capability is further increased to 180 metres, which is perhaps not quite as far as ideal but every little helps. Firepower is also increased compared to the 1B with an ER medium and ER small in each arm, but even with these changes the mech is still fundamentally cool running. The C3i computer is now mounted in the centre torso which is a much more significant change that it might first seem as you can afford to lose either torso and keep spotting - although not both thanks to that light engine. Endo-steel structure remains but there isn’t quite enough space left in the chassis for ferro-fibrous armour, so the protection now comes from standard plate and it's a half ton lighter than on the 1B. The arms and side torsos can shrug off a medium laser whilst the legs and centre torso can resist a clan ER medium. The head is finally capable of surviving a PPC blast and the Nexus II can afford to fall on its centre, if not its side rear torsos. In short, it might not be a lot of armour, but it is smartly laid out and the extra speed and jump capability means a machine of this type can make a serious attempt not to get hit in a way the old Nexus 1A could not. It’s unclear if the NXS2-A has supplanted the NXS1-B in production - the two machines are very similar, so it would seem to be redundant to build both at the same time. As to which is better, which do you prefer? Armour or firepower? Speed or survivability? Personally I’d take the 1-B over the 2-A given the choice, but I can see the case for the more modern machine.
The final iteration of the Nexus II takes it from the role of Level 2 spotter and into a pure scout loaded down with all the finest electronic wizardry the Inner sphere can devise. A relatively straightforward conversion on paper, the NXS2-B ditches the 2As jump jets entirely and replaces them with a Beagle active probe and Guardian ECM. The ER smalls are replaced by a head mounted TAG system and to complete the set the carapace is upgraded with Stealth armour. Despite its mechanical similarity to the 2A, this machine is much closer in capability to the Ostscout OTT-9CS - which is also used by the Word of Blake - only with stealth armour instead of jump jets (and double heat sinks, which the OTT-9CS really suffers for lacking). As with any mech that bristles with so much electronic warfare gear you need a plan to get the best out of it - semi-guided missiles on a networked missile support mech seems a good place start, but really you want a battery of Arrow IV launchers hiding a couple of kilometres behind you. Using the stealth armour and the C3 network together effectively also requires timing and forethought.
So, how do you fight one of these things? Well, if you have anything fast and armed with pulse lasers (you know, like a Dart) you'll make short work of a NXS1-A. Alternatively, simply standing still in an open area and picking it off with long ranged weapons as it comes to you tends to work too – although the AMS will prevent single hits from modest LRM racks from posing an existential threat to the target. The Nexus 1A absolutely must close to knife fighting range in order to hurt you seriously, but simply isn't fast enough or tough enough to survive closing in on anything heavier than it.
All the other Nexus' are much harder to tackle. The NXS1-B in particular is pretty tough for a fast(ish) twenty five tonner and both it and the 2A can actually get a decent defensive modifier out of their jump jets. Further, as C3 spotters they're likely to be less concerned with actually doing damage themselves in preference to providing good spotting data to their team mates. As such you can expect them to be orbiting a favoured target at 210 metres, generating the highest defensive modifier they can and sniping you with their lasers in vague hope rather than any expectation of getting hits. All the usual advice for tackling a light C3 spotter applies - bring a scout hunter with pulse lasers and an ECM then either drive them away or jam their network. The same goes for the NXS2-B, only now you have to worry about whether it’s spotting for a network or hanging off at a comfy range for the TAG with its stealth armour engaged. A good gunner behind that C3i and TAG can almost guarantee a deluge of pain no matter what your opponent has brought to the party so you need to kill it or keep it away as best as you can.
As you would expect of a machine associated exclusively with Comstar and the Word of Blake, both the Nexus and Nexus II officially went extinct after the Jihad. Normally I'd comment how that's a shame, but I find it difficult to believe that anyone much mourned for the loss of the Nexus. None of the factions left standing had a lot of use for a light mech geared almost entirely around carrying a C3i computer and the NXS1-A is just plain bad – not that I expect many of them were left after Comstar used them against the clans, imagine facing down clan-tech pulse lasers in one of those death traps. Yeech!