usage - Meaning of ~つもりではいる in that sentence

I don't understand the meaning of ~つもりではいる in this sentence :

そしていちおう手加減してやるつもりではいるが殺されてしまっても負けとなる。

And, although I'm planning on going easy on you, you will also lose if you happen to get killed.

I'm familiar with the ~つもり+である construction and I remember reading somewhere that でいる could sometimes replace である (not sure about that).

So is it でいる + は (and what difference is there between である、でいる and ではいる)?

Or is it で (て forme of だ) + 入る and in that case, what does はいる mean in that context?

Or something else entirely?

Answer

Yes, it's a combination of で＋いる with the contrastive は inserted. No, it's not で入る.

When you use 〜でいる instead of 〜だ・である, the emphasis is on the current state (or with 〜でいた, a past state). In your translation, that's reflected with the English present progressive "planning on".

In this particular example, the particle は is added to show contrast with the following clause.