A BIG no on the 60k temperature cap. Too damn spicy. I'd rather have you lower his intermediate tier maximum heat output to 3k celcius and high tier to 20k. The temperatures you listed are enough to melt through any armor currently found in this multiverse, given that it isn't a mile thick. Though i suspect that such temperatures would even ram Erde's earth dome down in one blast. And what makes them outright unacceptable, is also the fact that they come in the form of never-ending lightning bolts, unlike the rockets of Green's mecha, which while having equal damage output, are finite, slower, and are used by a humongous target of a character.

And you will probably have to add a turn limitation to his strength boost, and nerf it down in armor mode, to somewhere around 60-70.

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EDIT: actualy, nevermind on the high tier heat. While i still insist on having intermediate heat output NO HIGHER than 5k, seeing that Green's mech boasts withstanding nuclear explosions, the core of which reaches around 100k celcius, something around 35-40k seems more than reasonable.