Board Thread:Questions and Answers/@comment-37191189-20181014115007/@comment-26447088-20181014192730

Iseult's skill chance is halved by Djehuti, so if you plan to eventually join a t50 union you'll end up switching over to Ba'al (Swimsuit) since she's more reliable and is better to burst with than Iseult.

As ExMachina2084 said, Nina and Quicksilver aren't good in the current meta of the game. Both units are too niche to be used in most finished competitive/end-game decks.

How many plat medals do you have? As ExMachina suggested, Meru (Christmas) and Diarmuid (New Years) would be your best options, as NY Diarmuid is what makes Fire one of the best elements in-game.

For your Pound, you might also want to consider Ampelus (Rain) as she's really good for getting guaranteed procs in UvU, Fortress Frenzy, and general questing. Not that good in Belly of the Beast and Rise to the Top where it's all one long wave, though, but in that case you could always switch to units like Galdrabok, Baba Yaga, Komachi (Hanami), Babbage (Festival), Enenra (Hot Spring), etc. depending on the deck's element and the other units.