Vemacitrin (Sanskrit) or Vepacitti (Pāli) is the name of a leader of the Asuras who figures prominently in many Buddhist sūtras.
After one battle he was made prisoner and bound before the throne of Śakra, ruler of Trāyastriṃśa, whom he treated with bitter verbal abuse.
Śakra bore his insults patiently, and argued that such patience was a sign of strength, not of weakness.
(Vepacitti-sutta, SN.xi.4) On another occasion, Vemacitrin and Śakra had a contest of verses, before a joint company of devas and asuras.
After a courtship that extended over many lives, Sujā married Śakra and Vemacitrin became his enemy's father-in-law.