As i'm understanding this, fan has a physical of 2 and close combat 5, so he rolls 7d10 to face punch. He can use fists of iron or cracked cell circumvention for a 2x boost. but using ccc requires activating his tattoos for 1 willpower and 1 essence, so he can't use both in the same round until he gets to essence 3. This stacks with the relic armor 7x boost for a total of 9x(or 11x when he can spend enough essence to activate foi,ccc, and tattoos in the same round. if charms stack...)
So, if fan is face punching a mook, in armor with charm stacking, he gets 7d10 dc6, difficulty -9, success x9, and difficulty below minimum gets turned into extra dice. minimum difficulty is 3, I think, so 13d10 dc3 x9.
but a human chaos champion probally has chaos blessings, though I doubt they go higher than lorgar, even if the chaos champion focuses on combat. They might have maxed out physical and combat, but not mega-attributes because none of them were obviously inhuman when we saw them. They're low tech too, so any equipment boost is from a daemon blade or something. let's say 4x and 2x, for a total of 6x. That's lower than fan, so he doesn't get to ignore it. Against that hypothetical high end human chaos champion, fan would be rolling 7d10 dc6 -3 x3, 7d10 dc3 x3 against cc's 10d10 dc 6. Is that right?
edit: but relic machine spirit lowers difficulty by 2, so its
vs mook - 15d10 dc3 x9, ignore 1s , avg 108 successes
vs peak human champion - 9d10 dc3 x3, ignore 1s, avg 21.6 successes
and his attackers have +2 difficulty with ranged attacks, which don't even affect fan unless they have super heavy weapons.