Boom Boom

Boom Boom is a high priority pet as it significantly increases Medal Buff at 5* as well as allowing each battle drummer to increase the cap on the Medal Buff from the time shop.

Hero Couple (Battle Drummer)
Upon reaching 5* causes the Battle Drummer to provide some minor support buffs for other units.

Acquisition
Spirit Highlands Pet Shop
 * 5-16 (3 Frag)
 * 9-15 (3 Frags)
 * 11-20 (3 Frags)
 * 18-11 (1 Frag)

Available for Gems, Guild Coins and Honor Coins.

Secret Shop

Available in the Secret Shop - 5 excess fragments for 2 Boom Boom fragmnents.

Skill 3 - Awakens the hidden special ability of Senior Battle Drummer

 * Increase attack range, critical damage, and critical rate of all units by 5%.
 * Increases movement speed and attack speed of all units by 3%.
 * On first appearing, increases the movement and attack speed of all ally units and randomly casts physical immunity or magic immunity shield.
 * When included in team, medal buff increases by 30%. (Special skill 5 raises 10% to 40%).
 * Max medal buff increases by transcend units in Time Shop. (10% for 5* and 20% for 6*).
 * Gold level limit of Battle Drummer increase (Senior - 0, T1 - 10, T2 - 20, T3 - 30).
 * When included in team Battle Drummer increases Medal buff by 50% More (T1 - 15%, T2 - 30%, T3 - 45%). These buffs are halved in the Time Shop.