If you have Zhongli, it is possible to do the challenge even less than 30 secs. If you have not, use other shield(noelle should be fine)

I wish there was a poll for which ending people liked

I seriously love this Hangout, Traveller is just being Dad

Sayu and her Mommy Shrine Maiden Kano

The person who did not get the achievement, i did it with 55 sec remaining and still got it, either mine glitched or yours did

can you fix the mujina-class ninja achievement? i did it in less than a minute but i didnt get the achievement. dont you mean do it with 1 minute remaining instead? so i have to finish it in less than 30 seconds. so unhelpful

Can confirm CrossOmega's comment. In the Twinjutsu part, you need to finish the time trial of running up the river in less than 1 minute. It'll give the middle achievement here (the selected one).

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There is an achievement called "Mujina Cl*** Ninja". You need to finish the course in Twinjutsu in a fast timing.