Boss fight at end of "Black Tides" (Spoiler I guess)

So yeah... I just wanted to ask. I am currently at what I am assuming to be the final fight of the game >!(against Eamon and Nirmala) !<And... Is there some sort of trick you are supposed to be using? Because as it stands I can't do anything in this fight. They block everything n if they should be unable to due to their own attackstrings, they avoid midattack from your abilities and skills.... Their health pool is ridiculous.

After bashing my head against this for a while I started noticing the glowing glyphs on the floor. Thinking I had figured it out, I tried using them. But they also don't do anything. They do no damage and don't even stun them long enough for a single attack or ability.

Like... what even is this? This seems completely bugged to be honest. Heck, I turned the difficulty down to the lowest possible and its still not getting me anyhwere due to the two enemies straight up cheating the game's own mechanics.