The primary thing you do in Tlessa is kill monsters. This can be done through manual fighting or exploration.

Either way monsters play a big part of your progression, the primary driving force to keep you going.

Monsters drop random gear that scales with your character level to a point per plane and only ever to max of level 300 crafting/enchanting. This means players still have to craft and enchant to get the top gear.

Below is a list of monsters. You can filter by plane.

There are places in the world of Tlessa, such as special locations and Planes below Dungeons such as Shadow Plane, Hell, and Purgatory where monsters’ stats get higher than what’s listed here.

The stats above are base line, as if they were all on surface. Special locations on each plane can raise the enemy strength, while planes do the same but also weaken your character.

Gear is your only way forward. Whether you find it, buy it or eventually are forced to craft and enchant it.

Regarding Celestials

As you have seen in the list above, there are Celestials for each plane as well, most of the planes anyhow.

These creatures can be Conjured via the conjure button on the map, or in the drop down of actions for mobile players.

These creatures, most of them, will spawn every Wednesday at 1pm GMT-6 for 24 hours. They have, on this day, an 80% chance to spawn by you just moving around.

Killing them gets you rewards such as items, quest items, gold and a currency called: Crystal Shards which is used in Alchemy.

You can learn more about celestials, including how to conjure, here.