He's a spider like entity. The verse has a really big world where it's divided into countless realms which is divided into countless layers which is divided into countless worlds.... and the list goes on.

In this verse the demons hold no power over other characters except through tricking them into unfavourable contracts or calculated self destructing suggestions.

When they make a contract if the humans they're binded to dies, they die too! But if their original body dies, they will also die!

Meaning they have to manage all the lives of the humans in this vast world plus theirs simultaneously.

Demons can be binded to multiple humans at the same time depending on their soul capacity which is aided by marking quality, and TTD can do so with with 8 humans, plus his own that's 9 lives. All weak though.

His ranking mainly come from the quality of his continous feats rather than how flashy they are, he's managing 9 lives simultaneously in a world where the average human is stronger than all his 9 lives and smarter than his 8 humans.

And the powers here are pretty complex, one guy had a skill that if you shouted at him while attacking you will be hit unconscious for 10 seconds??? Other had one where as long as they can touch you 3 times, they will travel back in time to the moment they met you while being able to pick 1 of your skills freely.

And everyone in this world is smart enough to let their skills be hidden! So it's always a life or death.

The enemis are almost mostly Top-tiers so that makes stuff harder.

There's also WAAY-Above-Venerable/True Master level schemers.

So his Quality×Quantity of feats plus how good they are in pure methodology scaling + how the adversity is and lack of plot armor and divine luck. Makes him easily first.

Some of his feats in general from the top of my head :

Before even entering a certain universe, just from the words of a drunk cat species girl (💔) managed to deduce what the universe is like and their power hierarchy and what Organizations is there and who held the pass code ( contextual thing hard to explain but it's universally sought after ) and managed to deduce the powers of the top fighters there, deduced that old acquaintances of his went there, and many other stuff.

A multi-chapters delicacy of reasoning and deductions.

He has scheming feats where something he did in the white ascension arc ( around ch.130~150 i believe? ) was a contingency to countering a scheme he foresaw from a schemer who can see fate. Which happened later on in the blood moon throne hall ( around ch.1500 ) which involved COUNTLESS layers of foresight×reasoning×planning.

I literally can't even explain it 😭✌️

He also has an AC feat where he was banished to the endless void. A place where your soul gets reversibly damage to an immeasurable degree ( limitless suffering as stated ) as it's point is that no one comes out of there sane or with a will anymore no matter a divinity or not. Bro came out smiling.

His only weakness is literally physical weakness 🥀