CommentStreams:F6364fa8bb33386540e2e94d4301e37b

You can, in a way, as long as you almost 5-star the second, your choice which.

In the current event you have these options after you 5-star all week 1/week 2 cards:

1) 5-star Viscountess (NO5) + Sultan (OA5) (and thus Cruel Duchess (NO7)) to complete the Noble set.

2) 5-star Sultan (OA5) and be in top 100 to get 5-star Desert Avatar (OA7) to complete the Oasis set.