This is Chloe Genus from Conception II.

Her base prompt:

c2ch1o3, purple eyes, red hair, purple bow, hair bow,

Her default outfit:

black thighhighs, fingerless gloves, ponytail, pleated skirt, zettai ryouiki, black gloves, armband, boots, holster,

Her battle outfit:

thighhighs, underboob, navel, garter straps, panties, underwear, armpits, battle armor, detached sleeves, boots, cleavage, revealing clothes,

holding energy gun,