Elder Tremor Fully Upgrade maybe
Slow But Sure : When First Strike Elder Tremor deals more 15% Damages. Reuse it every 10 Second (Fully Upgrade 25% 2 stars)
Immortal But Weakness : When Active the skill Elder Tremor Take only 25% damages but Reduce Attack 75% for 20 Second and Can deactive it. (Fully Upgrade Attack Reduce 65% 1 stars)
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abandoned tower Fully Upgrade maybe
Cured Bolts : Every 3 Second can shoot Bolt Deal 55 damges and get damges 20 damges over time every second for 3 second. ( 1 star: Deal 58 damages, 2 stars: Deal 60 Damag