Meaning of かけやがりまして in 勝手にヒーリングをかけやがりまして

Question

What is the meaning of かけやがりまして in 勝手にヒーリングをかけやがりまして? Should I read it as かけ + やがりまして? If so, what would the inflection of やがる（り）＋　まして　mean when used together with かけ? And what would the meaning of かけitself be?

I checked in the dictionary and it seems to mean "Credit", but "To have the nerve of credit(?)" doesn't seems to make sense.

Answer 1

• 勝手に in this context means "without someone's permission", "all by himself", etc.
• かけ is the continuative form of かける, which is "to cast (a spell)". It's the verb you need to use with a magic spell. For example, 魔法をかける means "to cast a spell/magic". See the 14th definition here.
• やがり is the continuative form of やがる, an auxiliary verb used to express disdain. It's like adding a sense of "darn" or "f**king" to the main verb. This means the healing spell was somehow annoying to this speaker. See:
  • How to use the inflection "やがる"?
  • What does しやがって imply? shiyagatte doesn't seem to show up directly in dictionaries
• ます is just a polite marker. Maybe this person is reporting this event to his boss?

勝手にヒーリングをかけやがりまして
[He] cast a healing (spell) without [my] permission!