These may be used to enclose supplemental material, minor digressions and afterthoughts.

Parentheses

Explanation:

This is the punctuation mark that should be used in these cases. Parentheses are used in order to add material that is supplemental and is meant to clarify a statement. They can enclose a word, a phrase, or an entire sentence, and they always come in pairs. Parentheses also help you include information that is an aside, such as an afterthought.

beowulf sets out on his journey for daneland. -- 1

hrothgar welcomes beowulf. -- 2

beowulf waits for grendel to attack heorot. -- 3

beowulf succeeds in defeating grendel by tearing off his arm. -- 4

beowulf fights with grendel’s mother. -- 5

beowulf sets out for his fight with the dragon. -- 6

beowulf sets out for his geatish homeland. -- 7