Thoma is a four-star Pyro polearm user and a close aide to the Kamisato family. He performs as a shielder and off-field sub-DPS unit, with the ability to apply Pyro every few seconds.
However, his shield and off-field damage suffer from split scaling (HP vs. Attack), so he must be built specifically for his role in your team. While Thoma is a little complex to build, putting in the effort pays off as there are very few Pyro shielders in Genshin Impact. Here are some of my recommendations on how to build Thoma, including his best Artifacts, stats, weapons, and teams.

Best weapons for Thoma in Genshin Impact
Given the number of useful polearms in Genshin Impact, Thoma has a plethora of weapon options to choose from. Out of these, I recommend sticking with four-star options as applicable five-star polearms are better allotted to your DPS units.
Five-star options
Four-star options
Three-star options
Related:Genshin Impact Hangout Event: Thoma Guide
Best Artifacts for Thoma in Genshin Impact
Thoma’s Artifact stats are highly dependent on how you want to build him. My recommendation is to mix and match until you reach your preferred shield and Burst ratio. Just because you build him as a sub-DPS doesn’t mean foregoing the HP stats entirely, as it can be useful to bulk up his shield.
Thoma is a character who must be built intentionally. Choose any of the following Artifact sets based on how you plan to use him:
Best team for Thoma in Genshin Impact
Thoma is a fairly universal character who can slot into any team comp thatrequires Pyro. Be careful not to place him in comps where adding Pyro can destroy your intended Reactions, such as Freeze, Bloom, Superconduct, Quicken, and similar teams. Instead, Thoma can be used in the following:
For more on Thoma, check out ourGenshin Impact Thoma farming guidehere on Pro Game Guides.