Honestly, I just use Kal'tsit and use Mon3tr as a pseudo-fast redeploy to kill all the little things at the bottom, (Top one first, Middle one second ((also, be careful about the wave that will come, since maybe Ulpianus may leak one or two enemies, so place Mon3tr in a position where it can kill the calcification enemy and any enemy that leaks)), and Bottom one last) and use Ulpianus S2 in the exact same spot. Once all the little things on the bottom right are killed with Mon3tr, I place it behind the barrier of the top little thing and let the stage play out. When the last three big ones with the Nervous Impairment DPS go to Ulpianus, he'll be stunned, and one of them will leak and fall right into Mon3tr, and then you can just activate Kal'tsit's skill and boom. Just Kal'tsit and Ulpianus can do this stage.
Mulberry can be replaced with any elemental healer, and Kroos can be replaced with almost any ranged unit (including e0 lv1 Lucilla)
Honestly, I just use Kal'tsit and use Mon3tr as a pseudo-fast redeploy to kill all the little things at the bottom, (Top one first, Middle one second ((also, be careful about the wave that will come, since maybe Ulpianus may leak one or two enemies, so place Mon3tr in a position where it can kill the calcification enemy and any enemy that leaks)), and Bottom one last) and use Ulpianus S2 in the exact same spot. Once all the little things on the bottom right are killed with Mon3tr, I place it behind the barrier of the top little thing and let the stage play out. When the last three big ones with the Nervous Impairment DPS go to Ulpianus, he'll be stunned, and one of them will leak and fall right into Mon3tr, and then you can just activate Kal'tsit's skill and boom. Just Kal'tsit and Ulpianus can do this stage.
if i use eyja alter is she better than mulberry in this strategy?
Yep, eyja alter is almost always better than mulberry
All elemental healers should work even if you do not use their skill