The similar adjective triumphal means involving, relating to, or celebrating a triumph.

Is triumphantly an adverb or adjective?

triumphantly adverb - Definition, pictures, pronunciation and usage notes | Oxford Advanced Learner's Dictionary at OxfordLearnersDictionaries.com.

What type of word is triumphantly?

having achieved victory or success; victorious; successful. exulting over victory; rejoicing over success; exultant. Archaic.