Which one of these units do you think I should 6* first (for arena)

[icy valve]

finish pve first. that means everything here:

?progression

[tawny grotto]

Scenarios > GB12 > ToaN100 > S+ Ranked Water & Fire Rift > ToaH100 > Tricaru > Bj5 > Lumel b5 > S+ Rank All Rifts

(Text in ?thisformat are commands, type these in #bot-commands to get the guides!)

If you are just starting the game see
?beginner

READ THIS, ?progressionexplained gives a more in-depth explanation of the above progression