I'm wondering if it isn't the other way around and the Abyss watching him was what caused the War God UI to come into being. We once thought it was like the Demon King Order another Order but when Chaos UIs descended it was made clear that UIs are more widespread and the WGUI made its position as above the fight between order and chaos very clear: Both fight the apocalypse so I don't give a shit. Use them as you see fit. In that way being accepted as War God by the "System" as it called itself back then (when the author wasn't expanding the scope of the novel every arc) would possibly be the test. And the Abyssal form would either be access to all the functions or something unlocked at a certain point but hey I may just want to get answers to some of the very old questions in the novel where we'll possibly never get answers ;P Another such interpretation would be the corpse on the pillar being some conscious form of the Abyss, we got a new name for beings like it and the knowledge that multiple of them exist from Lin or the top Combatant of Humanity (can't remember who it was) but that's about it for its identity, maybe its a pillar god?

back when the strife zones were sealed GQS had the last message in the newspaper after which it crumbled down to reveal the black cloth that was a communication device of the Blade Edge Pledge ;P

nope, the sinful creature that was sealed away in the drifting sands world. the one that sent GQS through back through time for one week in the first place.

And just imagine the bill Barry and Kitty created for him once he returns to eartth.

Remember when they threw the 7 colored spear out of Huang Quan with the Grand Tian Mountain? Someone picked it up and recognized it as a nice spear - guess we now know what kind of being it was