Let’s come up with new “war machines.”

All machines can be kept. Add upgrades for ballistas and tents, depending on the race. And change the model slightly upon upgrading. Here is my proposal:
Inferno - Ballista: Essence Theft - Upon killing n creatures, there is a 40% chance that n:5 imps/devils/imps will appear, i.e., 5 times fewer than those killed. The chance percentage depends on the Gate Opening skill. Basic-40%, Advanced-60%, Expert-80%, Master-100%.
Tent: Sinful Mana - There is a 40% chance that upon resurrecting a cave demon/lord, it receives one single-use free darkness spell of circle 1-3.
When I say "resurrection", it does not mean that the entire squad must have perished.
Sylvan - Ballista: Entwining Bolt - There is a 60% chance that "Slow" will be cast upon hit, and a 30% chance that the unit will be "entwined". "Entwining" does not affect large creatures.
Tent: Lucky Healing - Upon healing, there is a 25% chance that the unit's luck will be increased by 1 for one turn.
Necropolis: Ballista - Rotting Shot - There is a 40% chance that upon hit, the unit's morale will be reduced by -1. Does not affect undead.
Tent: Cultivation - Upon resurrecting creatures, an additional number of resurrected units are added; the number depends on the unit's level and the number of units you are healing. It looks like this: level 1-3 1d20, level 4-6 1d10, level 7 1d5. That is, the number of resurrected units appears in proportion. Simply put, I had 60 zombies, one was killed, I resurrected it, and received an additional +3 zombies.
Dungeon - Ballista: Cunning Strike - The shot pierces n% of defense. The percentage depends on the attack skill. Basic-20%, Advanced-40%, Expert-50%. Also +5% for "attack" and "archery" skills. Total maximum of 60%.
Tent: Hydra Blood - Once per battle, the regeneration of a hydra/cave/chaos hydra can be transferred to another Dungeon unit. Regeneration parameters remain the same. The hydra itself loses its regeneration. To activate the ability, you must click on the tent's spell book (assuming you must have the "First Aid Tent" skill).
Academy - Ballista: Chaos Charge - Upon hit, there is a 60% chance that "Magic Arrow" will be cast, a 30% chance for "Lightning", and a 10% chance for "Chain Lightning".
Tent: Obsidian Tent - When healing obsidian gargoyles/obsidian golems, a minimum of 3 creatures are resurrected.
Haven - Ballista: Punishing Sight - Upon hitting a creature, when the unit shot by the Ballista attacks your unit, it deals only 70% damage, while 30% is "taken" back by itself. Upon hitting another creature, the effect is removed from the previous one. The effect lasts until the end of the battle, until another unit is hit.
Tent: Holy Calm - You can "heal" an enemy unit, and with a 40% chance only for that unit the "Holy Word" spell will be cast on the next turn. With Expert light magic +10% chance.
Fortress - Ballista: Guidance - Upon hit, there is a 20% chance that all Fortress archers will shoot at the same unit the ballista hit. With the "Archery" skill, the chance increases by 5%.
Tent: Runic Tent - When healing a unit, it may be given one free rune with an n% chance, corresponding to the unit's level. Level 1-3: 50% chance for a circle 1 rune, level 4-6: 40% chance for a circle 1-2 rune, level 7: 30% chance for a circle 1-3 rune.
Stronghold - Ballista: Roaring Bolt - Upon hit, there is a 40% chance that the "Fear" effect will be applied, and a 20% chance that the "Berserk" spell will be cast. For those with immunity to the aforementioned, the effects will have no impact.
But this does not mean that if a unit is immune to "Fear", it is protected from "Berserk"! And vice versa.
Tent: Blood Tent - When resurrecting a creature from the Stronghold faction, there is a 40% chance that only the resurrected unit's rage will be increased by 0.4 of the point total (not what remains to be gained) required for the next level. For example, I had 200 points (hypothetically!), and a total of 1200 points are needed for the next level. I have 1000 left to gain. I hit the 40% chance. This doesn't mean I get 400 points! (1000*0.4). It means I get 480 points! (1200*0.4).
So, those are basically my ideas. Since you promised, send them to Nival! Otherwise, did I work for nothing? And yes, by the way, if the ballista has several shots at once, the effect is applied only for the first shot.
P.S. Don't say "nothing should be changed"! This thread was created to provide your own ideas and suggestions for improving/creating new war machines! And not to express opinions on whether something should be changed.