Your +def Marth could actually be quite the wall for his team with a double Close Defense(A skill and sacred seal) and Quick Riposte or Swordbreaker to check Ayra/Mia/basically every other sword unit. This way not only he supports his team with his Spectrum Drive Falchion(this is in case you want to invest Divine Dew) and a Drive C skill, but he could also support your team by being the main tank. If you want a cheaper build(because you will need Joshua/S. Tiki/Sigurd for Close Defense, which isn't that cheap), Fury/Swordbreaker or Renewal is another option. His sacred seal can also be a Drive skill, to make him an even better support. Run Bonfire with those builds, he has the defense make it work.
Your +res Zelgius can reach very decent amounts of res with a Fury/Vantage build if you use the Distant Defense seal. He can even run Ploys if you give him a +3 res sacred seal and Fury(30 res is high enough to proc Ploys on most melees). His Fierce Stance is also a very good option here since he would still reach 55 attack when attacked, which is still pretty high.
Considering that Marth doesn't really have decent skills to fodder off(if anything, Spur Speed basically. Escape Route can be useful for some 1-turn Galeforce builds for example, but even then I've never seen it), and that Zelgius is still Zelgius(he can work with any IV set), I'd say you should keep them.
Hope this helped!
- Log in to post comments

Fate Grand Order
Dragonball Legends
IV Calc
Heroes