This is really just because I thought it would be cute. But if these two, or similar, were added to do piercing and shadow damage and the mecha knight kit was switched to doing elemental like the enemy mecha knights it could add some strategy in which to use when.
[Whole post from here edited to flesh things out and incorporate suggestions.]
Having one of each monster family would allow for balance, which is why there are now more than just two suggestions here, having two possibilities to do each type of damage and covering all possible vulnerability/resistance mixes. If trying to add in all of them was too much then a set of three covering all types of damage and a selection of resistances could still be used. Mecha knight kit is shifted to do elemental and share the vulnerabilities and resistances constructs normally have.
HP, defence and attack would be balanced to the current mecha knight at neutral values, with the vulnerabilities and resistances then applied as normal for the monster family. The attacks in each case are the normal ones for the monster type in question.
Places where mecha knight kits had previously dropped would now drop a random Ally Item. Ally Items stack with one another even if they are different and only three maximum can be carried. They would be used in reverse order to the order they had been picked up in, and could be dropped and rearranged.
Wolver Whistle
Gremlins have been training wolvers to guard the clockworks - why else would they show up with healers so often? - and this is what they've been using. Blowing it will cause a tame wolver to dig its way to you and fight alongside you for the level. Unfortunately tame wolvers are rather affectionate in quiet moments, and being jumped on by a fully grown wolver is enough to leave any knight stunned.
(Ally wolver, does piercing/normal, vulnerable to piercing, resistant to elemental, can inflict nearby knights with stun)
Appearance: Light golden brown with a large silver collar. Has a tail wagging animation that indicates it will leap at anyone who gets too close.
Infernal Transfer Slip
You don't *look* like a pit boss, but no good ever came of a devilite asking questions and this one will throw office supplies at your enemies rather than risk demotion. However, bureaucracy is a curse, devilite bureaucracy even more so, and it might be best to keep your distance.
(Ally devilite, does shadow/normal, vulnerable to piercing, resistant to elemental, can inflict nearby knights with curse)
Appearance: Similar to Sullivan's devilites in the arcade, a red-brown colour. Has a frantic, sweating animation, similar to a devilite getting scolded by a pit boss, to indicate when it is spreading curse.
Emberlight Flare
The gremlins of Emberlight sometimes scout the clockworks alone, and they carry distress flares in case one of them finds themselves in trouble. Setting off a flare will summon the nearest scout, a gremlin thwacker, to travel with you, but their own duties will prevent them escorting you further than the nearest elevator. They also carry flares and the unstable chemicals used mean they will occasionally light whether anyone wanted them to or not.
(Ally gremlin, does elemental/normal, vulnerable to shadow, resistant to elemental, can inflict nearby knights with fire)
Appearance: Dressed in white and carrying a bag over one shoulder in which firework-like flares can be seen. These will start sparking to indicate when the gremlin is spreading fire.
Slimy Pheromone
Tricking a slime really isn't that hard; after all, it has no eyes or ears. Unfortunately, they don't have a sense of self, and may try to m... merge with nearby knights, leaving a sticky, toxic mess.
(Ally lichen, does piercing/normal, vulnerable to shadow, resistant to piercing, can inflict nearby knights with poison)
Appearance: A pink lichen, which can grow if it merges with other ally lichens. It will become visibly sticky and lose its shape to indicate it is spreading poison.
Katnip Cantrip
How else would you summon a spookat from the realms beyond life? This one is enjoying its trip back, but has been far enough from life for long enough to carry the chill of the grave with it.
(Ally spookat, does shadow/normal, vulnerable to elemental, resistant to shadow, can inflict nearby knights with freeze)
Appearance: A white spookat with a golden glow similar to the sunshine aura within it. It fades to transparency while its glow intensifies to indicate it is spreading freeze.
Mecha Knight Kit
(Ally mecha knight, does elemental/normal, vulnerable to elemental, resistant to piercing, can inflict nearby knights with shock)
Appearance: Same as before.
....
I must say, not bad. Looks like you actually put some thought into this.
I applaud your effort.
As for the suggestion, I would support this, but I'm worried this will fall under 'combat-pets', which many forumers despise as a suggestion.
I'm also somewhat curious to see how this would be balanced. Same health and defense as a standard Mecha? Or sharing weakness of it's new monster family?