The name of this NPC is ひもりめ in hiragana (Himorime in romaji).
ひ is the most common kun-reading of 火.
もり corresponds to 防, but this is a nonstandard kun-reading even native Japanese speakers do not know. もり is usually regarded as a kun-reading of 守, which is a kanji with similar meaning ("watcher/keeper/protector").
め is one of the uncommon kun-...