What is next agent

By the way this is just my guess, this is not confirmed.
General:

I think it will be a controller that is earth themed. Earth themed because we already have wind (Jett), fire (Phoenix), and water (Harbor), and we need earth to complete it.

Abilities:
E ability: Smoke - a smoke that has dirt and grass flying around, blocking vision.
Q ability: Blind - kinda like harbor blind. It blocks vision using dirt.
C ability: Concuss - Earth comes up and concusses you. Never miss.

What do you guys think

it's definitely not eath themed I can tell u that already

https://imgur.com/a/U6wm2mJ

Someone tell Riot to look at this.

The theme was sound "amplify" Or resonance

leaks have already hinted at some sort of healing ability (which might be able to heal enemies too?), and with the "Amplify" player card teaser in game and some teasers in the Santiago animation, i think there will be some sort of damage amplifying ability. Its almost definitely a controller so 100% has a smoke too. My concept would be:
E - Sound Barrier: Deploy sight-blocking walls of solid sound on a minimap (similar to brim, but its short, line smokes)
Q - Amped Up: Deploy a field of sound that boosts damage of shots that pass through it
C - Soothing Melody: Deploy a speaker that will heal any ally or enemy in its radius
X - Beat Drop: Upon activation, nearby allies gain a stim, boosting movement speed and bullet damage, along with regeneration

Sage is already the earth agent, both in powers and play style. It's just radianite crystals instead of rock

It is a healing agent.

next agent is surprise crossover SERAPHINE