Meaning of せんと in these sentences

Question

In the fourth volume of 白銀のソードブレイカー I found these sentences:

一瞬の隙を狙って、エリザが背後から襲い掛かる。その魔剣がデュランダルの背中に突き立てられ、真っ二つにせんと刀身が迫る

[...]

刀身から放たれる光が全身を包み、すべてを支配せんとばかりに溢れ出し、あらゆるものが速度をなくし、完全に鈍化し、聖剣は徐々にデュランダルへと迫り、これで間違いなく命中する—

I thought it could mean something like しないと, I found this answer that seems to confirm my guess, and Jisho has an entry about this too, but with that meaning I'm not sure how should I understand those sentences.

I tried looking for it in my grammars, but I didn't find it, and a Google search didn't help solving my doubt.

If it's a negative form of する, I guess those sentences means something like:

• "The Demon Sword was thrust into Durandaru's back, and without cutting her in two the blade approached", which I don't really understand: if the sword is already in the character's back (突き立てる), what does it mean that's approaching? If instead it's in the process of stabbing her and has not reached her too, why "without cutting her in two"? If the sword hasn't reached her yet, it's obvious she isn't yet cut in two.

• "The light released by the blade wrapped her body, without controlling everything, it just overflown, everything slowed down, completely becoming dull, the Holy Sword approached Durandaru, without doubt this would hit...", which again I don't really understand: what should it mean that the light doesn't control everything?

Moreover, even reading them that way I'm not sure why せんと (with the と): it doesn't look like a quotative と, nor does it seem a conditional one, so I'm not really sure about how this structure is formed.

Answer 1

Short answer: those せんと in the question are different from the 関西弁「せんと」 and mostly the same as しようと: try to, about to.

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Grammatically the difficulty comes from different instances of ん.

Those in question is a conjugation of classical む, which is similar to modern う・よう.

む［助動］［（ま）｜○｜む（ん）｜む（ん）｜め｜○］活用語の未然形に付く。
１ 推量・予想の意を表す。…だろう。

２ 意志・希望の意を表す。…う（よう）。…するつもりだ。

The ん in 関西弁「せんと」(＝しないと) is a conjugation of negative auxiliary.

ぬ［助動］［〇｜ず（ん）｜ぬ（ん）｜ぬ（ん）｜ね｜〇］《文語の打消しの助動詞「ず」の連体形が口語の終止形となったもの》助動詞「だ」「たい」を除く活用語の未然形に付く。

せ is the 未然形 of する (the same as e.g. 確認せずに). と should be the と in とする, whose exact function I'm not sure.

So せんと in question mean

• The blade approaches, trying/willing/about to cut (it) in two.
• The light (...) flows all over, as if trying/willing/about to rule everything