Gunthra

Better than my -atk +Res abomination of an all fortress res skill and seal unit. Gunthra

If you really want another Legendary Hero from the Legendary Banner, then go ahead, but I would recommend saving for the next few banners though.

Gunnthra is a solid unit due to her excellent kit synergizing well. If you play her strengths well, she can become an excellent check against the majority of speedy units, which can help other allies get in and KO them.

Gunnthra is a fantastic unit...but her default A-skill is a deal breaker. Unless you have a dedicated Res or Def build that can reach sky high numbers, id never suggest “Fortress” skills. 35 speed isn’t enough to reliably double and missing out on those 3 points of attack will hurt her

Gunnthra isn't especially good unless you know what you're doing. Blizzard tome can be devastating if you debuff the opponents enough; I don't find her especially dangerous with her base kit.

Are you relatively new to the game?

She's going to wreck stuff with Veronica if you got her. All those debuffs on top of her reverse bladetome is going to put some serious hurt on a lot of units.