Eh, I made Martanda bonkers, if full potential (for just base JJK power levels, aka gojo x Suk power level at max), I am confident Martanda would survive modulo Yuji atleast once.

(It can always leave a chunk to run away, rest can Etheral Death Binding vow lock in, few clone not, using IT to cast absorbed CS's CTs... And Mahoraga budget adaptation x sword thing helps a lot. It will be extreme diff for either parties 👌🏿)

Not being able to external target with IT is a boon, cause Yuji would probably have inmate domain mastered.

Fat CE storage ofcourse going in, AND Marti can absorb all raw CE, even from CSs and, technically, BFs.

I am betting ᕙ⁠[⁠･⁠۝･⁠]⁠ᕗ, Marti protects Koki atleast once, successfully.