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Gotthard is useless for Pontiff, he rarely survives the first phase
Because it's YOUR job to keep him alive until phase 2. You summon him together with Anri (she is the tank in this battle) and then "manage" the fight, always keeping an eye on his lifebar and draw his attention if necessary. SL1 proofed tactic. Multiple times.

I killed pontiff in my first try with his help, and he did not die. You are just a dumbass who let he tank all damage.
Really I just use him as bait while I attack Pontiff from behind.
My theory is that Gotthard fled the castle when Oceiros went mad. So once he escaped he thought that maybe he could use the help of the Ashen Undead to finally kill the king, which is why he left his sign. Unfortunately, he never made it to Ocieros, which is why his corpse is found outside of the Grand Archives. Either way, he was a trooper...
Maybe you thought about it a little too hard
holy***** i summoned this guy for pontiff and he tanked everything and survived. I just attacked the pontiff and while this guy kept this attention. NG+ btw
You must have the wolf of farron covenant equipped for his sign to show up outside the abyss watchers.
Not true, just saw it with no covenant equipped.
should change his name to black hand *, literally stood there and stared at me while i soloed pontiff, *****ing useless *****
He cannot be summoned for Abyss Watchers if you've already summoned Londor Pale Shade.
My theory is that he asked by Emma to help those who were hunting down the Lords of Cinder. He chose to do this, feeling that his duty to his kingdom was greater than his duty to the princes (which put him at odds with Kamui). He came to help with two of the most essential fights in the Unkindled's journey, and, upon watching their defeat of the resurrected Lords of Cinder from the shadows, Gotthard went back to Lothric Castle to unlock the Grand Archives. However, in the time that he had been gone, the Pilgrim Butterflies appeared, and animated the Dragonslayer Armor. He managed to get past it, but he expired shortly afterwards.
Since I didn't see Sirris' sign at the Abyss Watchers fight, and I wasn't going through Anri's questline, Gotthard was my go-to summon for the Watchers and Pontiff. I don't know if how competent he is depends on how much of a casul you are (I think I'm in the filthy category), but he helped my strength character whittle them down before I smashed them. That being said, I ended up soloing the Watchers because I ran out of Embers, and he didn't live through the Pontiff fight, but I'm still holding on to his twinswords.
So has anyone figured out why his corpse has Onikiri and Ubadachi on it?
Why is he dead before the grand archives?