Valhalla vs Heaven

Valhalla and Heaven both are nouns.

Word	Noun	Adjective	Verb	Adverb
Valhalla	Yes	No	No	No
Heaven	Yes	No	No	No

As nouns, Heaven is a hypernym of Valhalla; that is, Heaven is a word with a broader meaning than Valhalla:

Valhalla: (Norse mythology) the hall in which the souls of heroes slain in battle were received by Odin
Heaven: a place regarded by various beliefs as the abode of their deities; also a place where good people are believed to go after death

Valhalla (noun)	Heaven (noun)
(Norse mythology) the hall in which the souls of heroes slain in battle were received by Odin	a place regarded by various beliefs as the abode of their deities; also a place where good people are believed to go after death