Thoma is a 4-Star Pyro Polearm character from Inazuma. He serves as a dedicated shielder for your team.
Both of Thoma’s Talents provide shielding. When he casts his Elemental Skill, “Blazing Blessing”, he strikes his opponent in an AoE and summons form a “Blazing Barrier”. This Shield scales off of Thoma’s Max HP and is 250% more effective against Pyro DMG. When he casts his Elemental Burst, “Crimson Ooyoroi”, Thoma performs a spin attack and summons a “Scorching Ooyoroi”. In coordination with your active character’s Normal Attacks, this aura summons a weaker Blazing Barrier and unleashes a Pyro attack called “Fiery Collapse”. If Thoma gains a new Blazing Barrier while one is currently in effect, the DMG absorption of the shield will stack and its duration will be refreshed.
Theoretically, Thoma’s Shield ought to be quite good. At maxed stacks, its DMG Absorption actually scales higher than that of Zhongli’s Jade Shield. The stacking mechanic also gives a lot of resistance to interruption. Even if your opponent is constantly breaking through the Blazing Barrier, your active character is able to avoid getting staggered so long as they’re gaining stacks to reup the Shield.
That said, the Blazing Barrier has some massive flaws. For it to be competitive against other Shields in the game, you have to spam Normal Attacks and let’s face it, that is more work that needs to be done compared to a Shield that simply requires the press of a button. That you have to perform Normal Attacks to stack the Shield also makes Thoma impractical for characters who seldom use them in combat. Most detrimental is the fact that Thoma’s Elemental Burst costs 80 Energy. Not only do you need to stack HP for Shield Absorption, you also need to stack Energy Recharge in order to actually use said Shield to the fullest.
You would think with Fiery Collapse, Thoma can serve as a Pyro Sub DPS. Unfortunately, Thoma frankly sucks at this job. At Lv. 13, one instance of Fiery Collapse has a multiplier of 123.25%. For context, this is slightly worse than Xiangling’s Pyronado at Lv. 3. With Thoma needing HP and Energy Recharge for his Shield, building towards DPS becomes rather difficult. Thoma’s A4 passive does give Fiery Collapse a flat DMG boost by 2.2% of his Max HP though this is hardly enough to compensate for a lack of ATK and CRIT. If paired with a Pyro carry, Thoma becomes a liability as Fiery Collapse can steal Elemental Reaction procs from your carry, potentially resulting in a DPS loss.
To Thoma’s credit, he does have a couple of Constellations that improve his kit. C1 gives a 3 second cooldown reduction to both of Thoma’s Talents when the Blazing Barrier takes a hit. This effect does only trigger every 20 seconds but that actually works fine as Thoma’s Elemental Burst cools down in the same amount of time. C2 is great for Shield uptime, increasing Thoma’s Burst duration from 15 seconds to 18. Those concerned with Energy should consider getting Thoma to C4 as it restores 15 Energy when he casts his Burst, effectively lowering his Burst cost to 65 Energy. C6 gives a 6 second 15% Normal/Charged/Plunging Attack DMG Bonus to Thoma’s team when a Blazing Barrier is obtained or refreshed. While this doesn’t improve on Thoma’s Shield, it does give him utility beyond Shielding. Due to the stacking mechanic, it can be very easy to keep this Constellation up.
Thoma isn’t the worst unit but his kit is undeniably botched. If his Shield could be stacked with all forms of basic attacks or his Elemental Burst costed 60 or 70 Energy, I think he’d fare a lot better as a unit. Although his Shield can be pretty durable, it is a lot of work to pull it off. Compare this to Diona or Zhongli who simply need the press of the Skill button to summon their Shields, not to mention they provide some other utilities besides Shielding. Also disappointing is how lousy Thoma is for Sub DPS. Considering that Xiangling is still the only viable Pyro Sub DPS in the entire game, it’s a huge missed opportunity not to add a second character for the job.
Thanks for reading!