Gigas, like all Beastmen have job types like players. The four you will see are Beastmaster, Monk, Ranger, and Warrior.

When close to a Gigas' level, all their TP moves can deal a lot of damage.

This spell can be soloed starting around level 30, No party is needed for the Qufim Island camp. Bringing a single High level helper can simplify things quite a bit, and get you the spell much sooner then level 30.

Not much needed other then Sneak and Invisble items, or spells, to get to camp if it's night.

Scattered about Qufim Island, in four general areas, as noted above, you will find wandering Gigas. At night there will be aggro from the Undead, and Bats, and there is magic aggro from Elementals when weather effects are up. Around the cerment walls, sound aggro weapons live. Take care in all cases. The Gigas can sometimes get close to each other, wait until they wander apart before you pull, as they can link by sight.

Your fights can be dangerous if you are hunting at under level 30. EM and T Giants can Hit hard, and the fights are dangerous. It's best to wait until they con DC and lower. Do not fight at night, as a drop into yellow HP will get the undead's attention, and quickly get you dead.

Giant Rangers are Rangers (duh!), and they will almost always make a ranged attack with a big rock first when you pull them. It can hit for a lot, so be ready with shadows, or a cure. Giant Trappers are Beastmaster Class, and will have a pet Leech with them, it is often better to pull the pet first, when the Gigas' back is turned, so you can fight it alone. Other local Leeches can link to the pet, so be careful! If the Giant sees his pet leaving as you pull it, he will link, and be cross with you!

Once you have safely pulled, the fights are straight up Head Butt and Bludgeon style ones, with Debuffs and Cures mixed in.

If you bring a single High Level Helper these fights are a snap.

Work your way to Lower Delkfutt's Tower. You may need sneak and invisible items to cross Qufim Island. Take care. Once you enter the Tower there are two good camps. Camp A is in the Hallway at H-9, and B is also in a hallway at G-10. From Both Camps you can pull Gigas from the nearby large rooms. Camp A has more targets. Be aware that there are sound aggro Bats in both areas, so be careful of them when you pull. Also, Gigas can link by sight. So make sure to wait until your target Gigas is alone before you pull.

Your fights can be dangerous if you are hunting at under level 30. EM and T Giants can Hit hard, and the fights are dangerous. It's best to wait until they con DC and lower.

Giant Lobbers are Rangers, and they will almost always make a ranged attack first when you pull them. It can hit for a lot, so be ready with shadows, or a cure. Giant Sentries are Beastmaster Class, and will have a pet bat with them, it is often better to pull the pet first, when the Gigas' back is turned, so you can fight it alone. Other Bats can link to the pet, so be careful!

Once you have safely pulled, the fights are straight up Head Butt and Bludgeon style ones, with Debuffs and Cures mixed in.

If you bring a single High Level Helper these fights are a snap.

There are many other Gigas about from which you can learn Grand Slam. All are either more annoying to reach due to aggro, or of higher level, thus requiring more help. With so many good lower level Gigas about in Camps 1 and 2, why bother?