Okey this is à good fight. They r both Very powerful. But i am gonna hv to go with Merlin here by à Very long shot. She has both the blessing of the DG and the SD and the knowledge of the demon realm "PORTOGORY". Her ability INFINITY is very dangerous and only She can dispell it.
She can stop time, cold forzen or fire burning for all eternity unless She herself does not dispell her spells, telekinesis, teleportations, immune to magic and curses, absolut cancle and so much More. She is by far the most powerful character shown in the NNT except the two gods.
Irene is very powerful, and has the best feasts in FT, calling à meteor from space, universe one, weather manipulation, energy blast, the all seeing eye, magic extraction, matter transmutation, Grant powers, dragon form etc. These is very impressive but against INFINITY and absolut cancle it is hard i guess.
Ive read many comments that say Irene is an ISLAND LVL, but the fact is it is Brandish Who is an ISLAND LVL, not Irene. And Irene is far More powerful than Brandish and has More magical powers. So Irene is More than an Island level.