Hi! Earth Spirit (Kaolin) is a melee strength hero, that possess a vast arsenal of disabling skills.
Earth in my opinion is the best Support/Roamer in the game no wonder the number of times he was nerfed. Earth Spirit has the longest reach, area slow in the game, and his high mobility makes him extremely fun and challenging to play. Being a strength-based support, he can still be built to be tanky(-ish). But his biggest contributions will be through his disables and TON of magical damage.

While not as powerful as before, in the right hands he can still dominate the early to mid game phase, dictate the pace of your team while frustrating the opposition like no other hero.
However, he is difficult to master. He has a unique mechanic , that forces the player not only manage his mana but also resources like managing his Stone Remnants. Also, you will need to develop muscle memory to properly deliver his combos and maximize his impact on the game. He mostly relies on roaming all over the map, ganking enemies for gold and xp. His high mobility makes its easier to gank enemy heros repeatedly disabling their entire early game advantage potential.

While challenging, none other support has the same “clutch” potential as Earth Spirit. A well-placed slow and silence can crush enemy team initiation or save an ally. But at the same time, no proper execution of his abilities will impact negatively your team. So Kaolin needs to be practiced alot.
This is my idea of how you can maximize your journey with our beloved rocky buddy :)

This is an in-depth guide of Kaolin, so I won`t be shy about the size of my points. Also, feel free to adjust my ideas to suit your playstyle.