As a standard foe, Garulas do not attack and are considered docile creatures. The randomly encountered Garula is impossible to lose against. After three turns of doing nothing, Garula will escape. They can be found near Walse Tower in the First World and in a forest in the Third World. Three turns will pass before it flees the fight.
A stronger Garula is fought as a boss within Walse Tower after it has started to attack people (presumably because it was possessed, given one of the knight's comments). The party try to stop it from breaking the Water Crystal.
When encountered as a boss at the top of Walse Tower Garula likes to throw its weight around and can be a difficult fight for a lower-level team. All of its attacks are physical, and can nearly (if not outright) KO any mage characters. Garula counterattacks an attack with a combination of attacks and Charge (a physical attack which causes continuous damage over time afterwards), often several times in one turn. The amount of time Garula counters seems to increase as its health decreases, making the fight more difficult as time goes on. Garula is susceptible to Toad and Paralyze. Both statuses will halt and reduce Garula's damage output.
One option is to make all party members Knights and have them constantly attack. With this setup, it is beneficial to consider changing one Knight into a White Mage or giving two Knights White Magic as their secondary ability to facilitate healing.
Another strategy is to use a party composed entirely of Monks and to have them use Chakra every turn to keep the party healthy. Garula will attack, which will cause the party to counter. This prevents Garula from countering with multiple attacks on the same turn as the counterattack does not register as a regular attack.
A simple strategy involves having a White Mage cast Silence on Garula before having a Blue Mage cast Pond's Chorus on it. Garula will cast Toad on itself next turn in an attempt to turn back to normal, but it will have no effect due to the Silence. It will continue to cast Toad every turn until it reverts when the Silence wears off.
Paralyze can be inflicted by the whip earned from Magissa. Level 9 Blue Mages using Goblin Punch from the back row will inflict increased damage.