Peak? For me would not be the recent annihilation ultron... But when he took over slovenkia or whatever and made hundreds of ultrons fromsecondary adamantium... That guy with so many extra bodys and shells would tire out brb before he finally destroyed the last body...
__________________ Quotes from Hia8:
"I claimed that the science is sometimes faulty."
"You don't understand. This is fiction. That means none of this stuff really happened."
"There is no writer to purposely ignore a character's natural ability just because it suits the story."
"in some cases because the writer knows that Character A will dominate Character B easily and refuses to allow this to happen for the sake of the story."
If not a "godblast" like Thor, BRB can def release a huge blast of energy from Stormbreaker. Also for this fight, assume BRB is fighting one single "real" Ultron.