Eldigan's A slot

I personally have a +spd/-hp Eldigan so I run LnD. That means his total stat change is +8/+8 atk/spd and -2/-2 def/res. He will still be physically bulky and has decent speed of 36 at 0 merges and is a solid budget build that has great synergy with Desperation due to his weapon built in Fury. But since you don't have +spd, then yes a brazen skill would be a nice alternative but is limited to a seasonal unit. It's up to you if 32 spd after Fury+LnD combo is good enough for you if you decide to do that build. With cavalry buff, he can go up to 38 unmerged. Otherwise, sturdy blow is a more solid option because by nature he is a bruiser as opposed to an assassin like for example Brave Lyn.