Nope, Astrid is the one requiring the lvl 13.

And yes, you are right, Nami is better. Oversighted her. But anyway, it's not like you are using lot of light tanks. Medium tanks are meta, better than heavy (for the cost) and light (for the cost²)

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Finally finished the mission 60 (and the end of the first part of the campaign, 20 special missions left). The last mission was very, very, very annoying (but by luck, managed to 3 gold star it at the first try, so I will not have to do it again). Karina Amelia combo carried me very, very, very hard.