である vs でいる for turning nouns into verbs


I always thought that である was a way to replace です, or the equivalent of
turning "noun" into "being a noun". However, In this ひぐらしのなく頃に fan art
piece,魅音 is saying

> ずっと沙都子の味方でいさせてよ

Which I think means "Let us always be your allies, Satoko"

<https://twitter.com/aru_aru14284024/status/1446053740025303044/photo/1>

The でいさせて looks like the causative て form of でいる rather than である. Is that
because 魅音 is talking about herself and her friends, sentient beings, and
therefore でいる should be uses over である?




でいる is "the progressive form of だ", so it means "to be being X", "to
stay/remain X", "to continue to be X". It has little to do with である.

  * 沙都子の味方でいる  
to continue to be Satoko's ally

  * 沙都子の味方でいさせる  
to make [someone] continue to be Satoko's ally

  * 沙都子の味方でいさせて(よ)  
(Please) let [us] continue to be Satoko's ally

See also:

  * [What is the difference between でいる and である in this example?](https://japanese.stackexchange.com/q/66270/5010)
  * [Why である instead of でいる？](https://japanese.stackexchange.com/q/93895/5010)
  * [What is the meaning/grammar behind noun + でいる?](https://japanese.stackexchange.com/q/62732/5010)




でいる is "the progressive form of だ", so it means "to be being X", "to
stay/remain X", "to continue to be X". It has little to do with である.

  * 沙都子の味方でいる  
to continue to be Satoko's ally

  * 沙都子の味方でいさせる  
to make [someone] continue to be Satoko's ally

  * 沙都子の味方でいさせて(よ)  
(Please) let [us] continue to be Satoko's ally

See also:

  * [What is the difference between でいる and である in this example?](https://japanese.stackexchange.com/q/66270/5010)
  * [Why である instead of でいる？](https://japanese.stackexchange.com/q/93895/5010)
  * [What is the meaning/grammar behind noun + でいる?](https://japanese.stackexchange.com/q/62732/5010)

