Combined with buff beams, this is an extremely useful skill against ogres, djinn and bosses. Defense boost also stacks with the Apprentice Guardian which can increase the DPS of select defenses even further.
Along with Hero Boost, Defense Boost drains the user's mana at an exponential rate while active. When the ability is turned off, it cannot be activated again for 15 seconds.
As of PC Patch 7.27, Defense Boost increases the effectiveness of towers along the following approximated ramp.
|Defense Boost Stat||0||100||500||1000||1500||2000||2500|