So from where you are at now, the you need 4x dark side ships at 4* to get the 5* executrix which is needed for the challenge, then a total of 6x 5* ships after. The fastest is to just buy the three geo ships from GW and Fleet store plus farm sun fac ship from fleet hard node 2a. You already have Silenber st 4* and can keep working it to 5*
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