the 'mugann spam' is a crap line anyway. fight starts with him vs non lelouch so he's there in the first place. if the dude's there he ain't taking off for no reason and is a bigger dick (gives more despair etc) by actually being there.
the idea still ends up being don't beat him by brute force and... that's pretty much how the entirety of the stranger geass powers worked, especially in NoN. bunches of powers deal with memories (altering, locking, seeing through, making them relive, etc) or certain commands to directly affect them (absolute obedience, love the other person, etc), involve time (stopping time and space, seeing into the future, knowing the future), or have some weird body not needed aspects to 'em. geass powers are extremely varied and the connection's pretty high level if the idea was to kill that series' incarnation of God, in the same series where one of the root powers is described as the power that returns all creation into nothingness and they've a central hub to go to all mutliverses as well. entirely different scale from the main series overall there, and much better at pretty much everything. which is good since there's a nice bag of tricks to work with in there.
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The future must protect the clone's past.
"Maybe it's a tentacle, molesting the planet itself. - Aschen Brodel.