Does it lower Def or something?
Shrink Body does 4 things. First, it decrease sizes of Mobs and then defend aoe ratios of the Mobs are also decreased, so if you use aoe attack, it can hit more Mobs. In addition, the smaller sizes of the Mobs will make Archer hit them harder by reduce the damage penalty from missile attack. Second, it has additional damage attribute which deal damage per the attribute level. This attribute makes Shrink Body good even only at 1 level that will help a lot of support builds which lack of attack skills. Third, it has the other attribute which reduce damages from Mobs. The last is the attribute of Swell Left Arm that let you get additional damage of Swell Left Arm from Shrink Body. This attribute needs 2 Shrink Body levels, so this spell levels should be 0, 1 or 2.
There might be some time when you should not use this spell if your party has some one who has some benefits from medium or large type Mobs.
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