It seems that from Trundle's lore that his bearing the curse of an entire tribe might actually make him less powerful than the average troll (or a troll that was at peak physical shape). It also seems as if his ability kit should be more similar to that of Dr. Mundo's with insane health regeneration. I love the champion Trundle and I believe he has a good kit (could use a few tweaks but nothing major) my issue with the champion is that his lore does not seem to match.

He bears the curse of the tribe, but he was also born with the gift of insanely fast healing. So, I guess the two balance themselves out.

What about the filthy pillar though and the other contaminate ground effects though....I guess I am not satisfied in why he can do these things and why contaminating the ground helps him the way it does. Is his curse finite? By spreading elsewhere is he in a sense buffing himself?

The contamination and whatnot are probably related to him being a troll. Not his disease. Perhaps they live in a filthy manner?

I think a big factor in trundle's kit is the fact that he bears a curse designed to affect an entire tribe of trolls with powerful regeneration abilities by himself. With that much powerful magic in one creature, he has to have some power of his own from it (not to mention his incredible regeneration abilities, god-worthy tolerance of pain, and overall trollness) which can be seen in his ability to control the disease and affect others, terrain, and strengthen himself with it (pillar of filth, contaminate, and agony).

I actually think Trundle's lore is one of the best lores of LoL. Because he's born with amazingly natural talent, he's basically punished for it. Severely. He has to live with the constant agony of his flesh melting away then growing back in a never ending cycle. Yet he keeps going, driven by the knowledge that if he dies, the curse that he bears would most likely go back to the tribe, and goes into the League of Legends (as a troll mind you, next to some of the most civilized/powerful races in Runeterra) and stands toe-to-toe with legends, monsters, and magic incarnate. Trundle has every reason to hate life and give up: having to deal with the prejudices that the rest of the world has against him being a troll, bearing a curse while the rest of your kind gets off completely free, and being held back from your true potential of basically being immortal. Yet he keeps going, marching to the beat of a tattered, yet still valiant drum (haha, get it? beat?).

tl;dr - get out of the lore section.

I always assumed his kit was a byproduct of his curse.

On the contrary!

Perhaps Trundle has shamanic blood in him, allowing him to manipulate his curse. It was mentioned that the tribe does have a limited amount of spellcasters. If Trundle is like one of those shamans... Then it is possible that is able to use it his advantage by to forcing his curse on others.

*EDIT*

You'll notice that three of his abilities harm his enemy, but buff Trundle. His bite saps their physical strength. His passive takes their health and gives it to him upon their death. His ultimate steals both health and defenses from the enemy by forcing it upon them, if only for a moment. This causes me to think that Trundle is not just an idle curse bearer. Rather, this curse is somehow making him *more* powerful. Regardless of whether his lore says it or not, he's found a way to use his curse offensively and defensively by means of magic.

Another theory might be the classic, "blame the summoners" approach. Trundle only has these abilities because he is empowered by their magic. It's the same idea behind how some Champions like Garen use their ultimates. Now, I don't like this approach as much, but it's possible that they are allowing him to manipulate his curse through their knowlege while their minds are linked. This makes him a bit less awesome using this theory, so I'm inclined to hope that he has found a way to manipulate his powers.

Anyways, just some thoughts.

I always thought it was funny that he essentially doesn't really fullfill his oath.