Emblem for Costume Thalassa and field the costume by default.
The costume gives up only 50 boosted health on the first cast—500 instead of 550—but its fully charged cast gives 800 boosted health instead of 650 and four turns of status-ailment immunity instead of three. Both versions can receive the costume-unlocked insanity resistance, so that is not a reason to prefer one form over the other. (GitHub)
Use regular Thalassa as a situational alternative when the enemy relies heavily on mana reduction or effects that prevent Special Skills. Her Cleric-class Manashield can be more useful in that matchup than the costume’s Sorcerer-class talent. For normal raid, war, and event use, the costume’s stronger second cast is generally more valuable. (empiresandpuzzles.com)
Open regular Thalassa’s talent grid and take these directions, reading the forks from bottom to top:
Left → Right → Left → Right → Left → Left → Right L–R–L–R–L–L–R
The costume inherits the same left/right choices, but because it is a different class, the stat labels displayed on the regular Cleric grid will not match the Sorcerer stats received by the costume. Follow the directions, not the apparent Cleric labels. (Empires and Puzzles Wiki)
| Fork | Direction | Costume/Sorcerer benefit |
|---|---|---|
| 1 | Left | DEF +18, then HP +36 |
| 2 | Right | DEF +18, then ATK +15 |
| 3 | Left | Healing received +2%, then DEF +18 |
| 4 | Right | DEF +18 |
| 5 | Left | DEF +18, then ATK +15 |
| 6 | Left | HP +36, then DEF +18 |
| 7 | Right | DEF +3% |
Including the mandatory nodes, the +20 build provides approximately:
- DEF +126 and +3%
- HP +72 and +3%
- ATK +30
- Healing received +2%
- Mana generation +4%
This is preferable to an attack-oriented path because Thalassa’s boosted-health values are fixed by her Special Skill; increasing her attack does not enlarge the 500/800 health boost. Her primary requirement is to remain alive long enough to reach the stronger second and later casts. Also, the grid’s “Healing” node means healing received by Thalassa, not additional healing delivered to allies. (GitHub)
Regular Thalassa remains usable under this shared route. On her Cleric grid, the same directions create a more HP-heavy build and include her +2% mana node, so the path does not render the regular form ineffective.
Changing Tides’ first stage normally takes eight tiles. It drops to seven tiles at approximately 15% total mana generation.
With the costume fully leveled:
- Costume Thalassa at +20: 5% costume bonus + 4% Sorcerer talent = 9% before troop bonuses. Use a troop providing at least 6% mana generation to reach the 15% breakpoint.
- Regular Thalassa on this route: 5% costume bonus + 2% Cleric talent = 7% before troop bonuses. She needs at least 8% from the troop for the same breakpoint.
Check the troop’s actual mana bonus rather than assuming its level is sufficient. The breakpoint is important: reaching seven tiles makes her initial ailment protection substantially more reliable on offense. (Empuzzled)
At the two Master Talent forks, choose Defense rather than Attack both times. The resulting extension is:
- DEF +180
- HP +100 from the mandatory nodes
Stopping at +20 is the efficient choice. Take her to +25 when she is a regular war-defense hero, a primary blue support, or one of your most frequently used healers; otherwise, conserve Master Emblems for heroes whose Special Skills scale more directly with attack or whose survivability is more critical.
Costume Thalassa works especially well with heroes applying long-duration defense ailments, attack ailments, or damage-over-time effects: from her second cast onward, she resets the durations of enemy ailments while protecting your team from receiving new ones. She does not cleanse existing ailments, however, and the fixed 800 boost can be insufficient as the sole sustain source in very high-HP content. (BobTheSnark)
Final setup: Costume Thalassa as the normal form, L–R–L–R–L–L–R, a troop that brings total mana generation to at least 15%, and Defense at both Master Talent forks.