Sebastian
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 The Royal Court Composer who is tasked by King Triton to watch over Ariel.
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| Kana | セバスチャン | ||||||
| Romaji | Sebasuchan | ||||||
| JP Set | 11 | ||||||
| EN Set | 10 | ||||||
| Class | Type | Attributes | |||||
| Event | Attack | Power | Upright | ||||
| STR | DEF | Trait Slots | Spirit Points | ||||
| 4213 | 4308 | 1 | 15 / 18 | ||||
| Strength Boost III +4 | |||||||
| Raises strength by 3 tiers for 1 turn. | |||||||
| Damage (Base) | x1.45 | Target |  All
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| Damage (3 dots) | x0 | Gauges | 6 | ||||
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 The Royal Court Composer who is tasked by King Triton to watch over Ariel.
| |||||||
| Kana | セバスチャン | ||||||
| Romaji | Sebasuchan | ||||||
| JP Set | 11 | ||||||
| EN Set | 10 | ||||||
| Class | Type | Attributes | |||||
| Event | Attack | Power | Upright | ||||
| STR | DEF | Trait Slots | Spirit Points | ||||
| 5433 | 5556 | 1 | 15 / 18 | ||||
| Strength Boost III +5 | |||||||
| Raises strength by 3 tiers for 1 turn. | |||||||
| Damage (Base) | x1.49 | Target | All
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| Damage (5 dots) | x0 | Gauges | 6 | ||||
| Damage (Max) | x | SAB Tier |  3
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Sebastian is an Event Attack Medal in Kingdom Hearts Unchained χ / Union χ.
In the Japanese version, Sebastian was available as a reward in the third High Score Challenge from July 29 to August 4, 2016. In the English version, it was available as a reward in the fourteenth High Score Challenge from January 19 to 25, 2017.