Pitlord feels like a mixture between Jakiro and ET. His pit is pretty much like a slightly different Icepath, including the slow casting, meaning you cannot chase with level 1. His Firestorm is like dualbreath, just without the slow and you can walk out of it while it deals a little more damage. Atrophy Aura on the other hand says you should go in and rightklick, or at least debuff. His ult is pretty much a mass relocate that has a longer cd. Why does the Manacost increase so much? Unless you were suprise buttfucked I like the longer activationtime more, while 10 secs per level does very little in comparison.
His Pit and Firestorm say stay away, his Atrophyaura says stay in while his ult has little synery with both, unless you count TPing after you cleared a stack for +dmg (where you should probably use a tp anyways) as synergy.
I personally liked the version where he had exploding corpses better, it felt more synergistic. Maybe give him bonusspeed while he is in the pit or at least make the cast faster. Currently his biggest downside, at least how I see it is his long-ass casttime, you can't really chase to use you meleeatack or use the pit, unless you leveled it up.
With that being said he does work well with Jakiro and ET and comboes they can be quite devastating. Jakiro, besides having somewhat similar skills, helps towerpushing with liquid fire and ET reduces enemy defences while he can also setup icepaths/pits or get help to land his ult. Pitlord himself can get both out of trouble, so jakiro being slow is less of an issue and ET can rightclick better due to the disables and atrophy aura. He could work nicely with enigma, too. Can they share a Jungle without killing things too fast?
I still would like some changes to make his skills better working together.
Other than that It feels, that despite it seems to work well together with his Aura, Vanguard feels kinda weak. Mek, despite Underlords limited manapool seems to make him way more tanky. Other than that I like Echosabre on him, since it kinda helps with chasing and he gets like 30 dmg if he stays in lane (also 65 dmg lvl1 :O ). Sadly it doesn't solve his manaissues, so Arcanes are core.
PS: Aghsidea: Firestorm casted on the TPtarget upon start of the cast and Pit upon arrival. Would also make leveling the Ult actually better, since you may be able to catch someone with both. Maybe also allow TP to heroes.