expression, i-adjective
nothing but; none other than; it is precisely
Used to emphasize that something is exactly what follows, often in explanations or when revealing an important point. Common in the pattern 他でもない〜から or 他でもない〜のだ.
彼が怒ったのは、他でもない、君のせいだ。
The reason he got angry is none other than your fault.
今日ここに来たのは他でもない、お礼を言うためです。
I came here today for no other reason than to thank you.
From 他 (ほか, 'other') + でもない ('is not'). Literally 'it is not other', used to stress that something is exactly as stated.