User blog comment:Kirakagomine/Basic Tips for Begginers/@comment-24990818-20140818101738

Bulk fusing 3 identical 1*s to another identical 1* (eg. fusing 3 WW to one WW) then using the leveled-up 1* as a feeder gives more exp and is more cost-efficient. The same effect can be achieved with 2 instead during fusion success events. So no, bulk fusion does have its uses.

Also, I find it inaccurate to say that attack reducers are useful for a defence team, as you have no control over the type of team that attacks you, so your attack reduction skill could miss entirely (this is especially pronounced at lower levels).

The general hiearchy for skills is: 1. Type boosters (both attack and defence) 2. Defence reducers (for tower and attack team filler) 3. Attack reducers (defence team filler) 4. Silver boosters/reducers (situational) 5. Self-boosters (bad)