Underground Base is the third stage in Alcatraz.
Le'boin appears as the main threat.
Squire Rel appears as peons.
Owlbrow appears as support.
Slowly build up money by stalling the Le'boins as much as possible. Once you have enough spawn Bahamut Cat to kill the Le'boins. A little after the initial wave of Le'boins, Owlbrows will start spawning along with one Le'boin. Keep stalling them and send out Titan to resist most of the attacks and to directly attack the 2 enemies. Continue this strategy until you win.