Well the briah is literally just a plus. So imma put this last part in here. @everyone who disagrees that Medaka copies Briah's because of (insert rule), i already explained WAY too many times. The End bypasses rules. How many did i list by now? Like 5 rules that Medaka bypasses and just gains the abilities. The End just makes Medaka have all the benefits of a skill while bypassing ALL rules even ones created by MUCH stronger beings such as Ajimu (even rules that create the impossibility of having any skill that is not fit for you). Via verse equalization, Medaka does the same to Briah and copies.
The Cost is 0. Because Briahs are not minuses, they are abnormalities. Thus they don't share Minus' trait to be resistant to erasure effects. Unless you show Briah's to have that kind of resistance it's impossible to just say "they resist", unless someone tried to do that and failed.
As for the rest, Medaka still has a bit too many skills to beat Wolfy.
1. All Fiction, it can erase any attempt at killing Medaka. (the dude attacked me, except he didn't. The dude is trying to soul hax me, except he isn't. The dude is trying to do anything to me, except he isn't)
2. Unknown Hero doesn't conceal anything, it removes something. The presence. Check my blog on all fiction to understand what it means to "remove presence" from something. It's not that he won't see her, he won't notice her, it's not that he won't sense her soul, he won't notice her soul is there, he will be sensing her soul, though UH makes Medaka unimportant to other people. The example i always give, it's not that you don't see a pebble on the road, you also do feel if you hit 1 pebble away subconsciously, you do sense it, it's just not important, you just walk over it without noticing anything different.
@Frohe's question "Can Bookmaker affect him?" Bookmaker absolutely destroys.