Brandish and Dimaria win.
Come at me.
Seriously though, every Spriggan so far has disappointed in a way:
Neinhart for being Neinhart;
Jacob for being, well, Jacob;
- Invel because once Gray got serious Invel didn't do shit, i expected much more from him;
- Ajeel because he's extremely arrogant and is currently being handled by none other than Lisanna and Elfman;
- Wahl because he was dumb against Laxus;
- God Serena hasn't disappointed, he just got unlucky;
- Bradman because he was deadly in the north, but when he started fighting Gajeel all of a sudden he was nothing at all, didn't use his curses correctly at all, and eventually suicided; though i admit Gajeel should have died alongside him;
- Dimaria because she toyed with people instead of being serious, got demolished by END and by 2 little girls;
- Brandish because of her incapability to chose a side, she never fought for real, and got one shto by Dimaria;
- Larcade: lame magic, got countered and defeated by Sting Rogue and Kagura, "trump card versus Acno" "only his mother can possibly defeat him" yeah alright.
- Irene is no different. She was impressive when she got introduced, when she had her little skirmish against Acno, with UO, with various enchantments. Her hype seemed deserved, finally someone worth the hype! (Someone not named August, since AUgust is the only Spriggan who didn't disappoint me too much).
But yeah, eventually even hyped beast get shat on. Irene got the fall-off-the-pedestal treatment, when she fought and was losing against Erza and Wendy. Erza that couldn't deal with Ajeel alone. Wendy that needed Ultear's counter to Age Seal, and TO Sherria, in order to not get stomped by Dimaria.
Yeah, at this point i don't really care at all about the hype about Irene, being massively superior to other regular Spriggans. Couldn't care less.
The trump card versus Acno was defeated by 3 mid-tier characters ffs.
I do not believe in any Spriggan hype anymore now, that's just how it is. I'm still reserved about August since he demolished CS singlehandedly so he SEEMS worth the hype, but i know for a fact that he'll get defeated eventually.
So yeah, imo Brandish and Dimaria can beat Irene. Individually they are inferior. Even exclusing hype, i wouldn't dare say that Dimaria > Irene (despite Irene not having shown a way to counter Age Seal) or that Brandish > Irene.
But as a team i do believe they would win, since Irene has been massively over hyped, and recent chapters proved it imo.