If you looking for Artoria Avalon/ 3rd ascension, check here https://civarchive.com/models/572607

PONY:

Castoria:

Castoria, green eyes, blonde hair, low twintails, ahoge, hairbow, half updoCastoria_staff(optional)

or you can use low twintails and ponytail simultaneously, cause her twintails is a little different than normal twintails

1st asc:

Caster1, C1_gloves, C1_hat, C1_belt, C1_pouch, C1_dress, C1_pantyhose, grey skirt, grey gloves

2nd asc:

Caster2, C2_hair_bow, C2_gloves, C2_hat, C2_pantyhose, C2_dress, C2_belt, C2_capelet, black gloves

Summer 1st asc:

SCaster1, Sum1_bikini, Sum1_hat, shrug (clothing), uneven legwear, Sum1_single_pantsleg

Summer 2nd asc:

SCaster2, Sum2_dress, Sum2_detached_sleeves, Sum2_fake_rabbit_ears, hairband, Sum2_thighhighs, Sum2_wrist_cuffs

Illustrious:
Castoria:

Castoria, long hair, Castoria_low_twintails, blonde hair, green eyes,
Castoria_staff(optional)

1st asc:

Caster1st, C1_shirt, C1_skirt, C1_hat, C1_gloves, C1_pouch, C1_pantyhose, C1_belt_buckle, Castoria_staff, brown footwear, boots,

2nd asc:

Caster2,C2_pantyhose, C2_beret, C2_dress, C2_capelet, C2_gloves, C2_bowtie, C2_hair_bow, C2_belt, C2_sheathed_sword

Summer 1st asc:

SCaster1,Sum1_bikini, Sum1_hat, shrug (clothing), uneven legwear, thigh, Sum1_single_pantsleg, Sum1_sandals

Summer 2nd asc:

SCaster2,Sum2_dress, Sum2_fake_rabbit_ears, Sum2_thighhighs,Sum2_wrist_cuffs

Ciao