Krishna says in Uddhava Gita 17.51 (Swami Madhavananda translator):
Swayed by his past works, a man through his attachment to Sattva becomes a sage or a god, under the influence of Rajas an Asura or man, and under the influence of Tamas a ghost or a beast.
and in Gita 9.25 Sri Krishna says (Swami Nikhilananda translator):
Those who worship the gods go ...
According to Manu Smriti, the different beings falling under Sattva, have further been classified into 3 sub-categories.
Lowest category under Sattva (Manu Smriti 12.48)
Ascetics and hermits, Brāhmaṇas, celestial beings, lunar asterisms,
and Daityas represent the first state partaking of ‘Sattva.’
Middle category under Sattva (Manu Smriti 12.49)
Yes, Vibhīṣaṇa also killed some rākṣasas during the battle between Lakṣmaṇa and Indrajit. Bow & arrow seems to have been his chief weapon.
Seeing Lakshmana and Indrajit, fighting with commitment to gain
victory one over the other, like elephants in rut, that strong and
valiant Vibhishana, wielding his excellent bow, stood there at the