the overload battery, a device of immense magnitude, is a capsule of heat that is fuelling a power cell within it that gives off a blast of ultimate destruction. it would need charging with heat first to fill a ammunition slot, when it is full knights can send the little beauty off with a button on the keyboard. it would come in a variety of options, concerning status's like fire, ice and so on, and would also come with star levels for a matter of things listed later on below, either like weapons and armour does or in some other form. would be individgual to other weaponns and reqiure its own slot, which should stay. you have to fill it up with heat, so it needs to be eqiupped, and it would be pointless putting it in a slot to use it once, twice, or three times, (varying on its level), would make it to costy to have fun with. meaning slot should be permanent.

this solves the problem of heat becoming useless to knights who are fully arranged, as when it s used it uses up the heat its storing, emptying and filling it will be satisfying, giving you a little extra to do.

would have all status types, fire and the like and would be in five stars like a sword or shield, with the following profile ( bearing in mind even a puny battery is powerfull, and damage changes to current tier level like ordinary weapons.)

1 Star - puny, puny status, 1 charge slot.

2 Star - weak, weak status, 1 charge slot.

3 Star - medium strength, medium status, 2 charge slots.

4 Star - good strength, good status, 2 charge slots.

5 Star - strong strength, strong status, 3 charge slots.

on all stars, it always takes a while to fill a charge slot, preventing it from unbalancing the game. about 3, 4 or 5 areans arenas worth, so quite a lot. it should be unleashed around you and alsways be instant, making it different to bombs. would be qiute strong against bosses but not as powerfull against ordinary creatures to avoid making it one sided on boss levels. only one can be eqiupped to a knight and a knight may only have one in his arsenal to prevent kinghts from using a ton of them over the course of just a few levels. after all this it may seem flawed, but its easy to remove them.
would look like a erupting blast of power when used, would not brake the battery itself and maybe its blast that fills the screen can be changed visually to please the eye of its owner, a little bit of customization. eg, a spreading ball around the knight, a ripple along the ground, a shockwave, a vortex of spirits, ect, and whatever it is it should always be 3 dimensional. meaning not just flat along the ground, but out in all directions.
unbalancing the game may seem an issue, but it will always takes a huge mounta of heat to get it working first. if it still seems unbalanced maybe it can take half a bar of health of your knight as its so powerfull. shouldnt damage other knights in the party, only the user.

Visually pleasing, and if your in a tight bit of trouble, a sure way of getting you out.
providing your health is at least one bar still. or maybe youve sensed everythings kind of lost, but you just want to go down in style!

"IF IM GOING YOUR COMING WITH ME!" obviously not going to work on a boss but still amusing.

i hope im not sounding too much like someone whos got a screw loose, if i am, i apologise.