Yugoloth Traits: A yugoloth possesses the following traits (unless otherwise noted in a creature’s entry).
—Immunity to acid and poison.
—Resistance to cold 10, electricity 10, and fire 10.
—Summon (Sp): Yugoloths share the ability to summon others of their kind (the success chance and type of yugoloth summoned are noted in each monster description). Summoning a yugoloth poses a serious risk. There is a 25% chance that a summoned yugoloth turns on its summoner, attacking immediately (and hoping for a reward from whatever was threatening the first yugoloth).
—Yugoloths can communicate telepathically with any creature within 100 feet that has a language.
Except where otherwise noted, yugoloths speak Abyssal, Draconic, and Infernal.
Here are the ability scores of similar-HD yugoloths...
Canoloth (6 HD, M): Str 19, Dex 10, Con 19, Int 5, Wis 17, Cha 12
Dergholoth (8 HD, L): Str 20, Dex 10, Con 21, Int 7, Wis 10, Cha 14
Echinoloth (8 HD, L): Str 22, Dex 13, Con 20, Int 6, Wis 8, Cha 11
Piscoloth (9 HD, M): Str 19, Dex 11, Con 15, Int 6, Wis 10, Cha 14
Marraenoloth (10 HD, M): Str 13, Dex 15, Con 10, Int 13, Wis 14, Cha 10
Mezzoloth (10 HD, M): Str 16, Dex 12, Con 21, Int 7, Wis 10, Cha 14
I’d recommend we make the least Small, the lesser Medium, and the greater Large. Int 9, 11, 13 respectively?