The etymology of Fenrir’s name is fen dweller, a fen being a swamp or marsh. In the eddas Fenrir isn’t talked about much he is chained by the gods because they fear him and the prophecy of Ragnarök. During the events of Ragnarök Fenrir breaks his chains and kills Odin this has led many Lokeans to refer to him as the chain breaker or the breaker of chains. Fenrir is Frequently associated with the ideas of just rage destruction, strength freedom and the struggle for it, as well as fighting against injustice and oppression. Because of this I associate him with the runes Thurisaz Hagalaz and Uruz. While I don’t necessarily see him as a war god, he is fairly close, and this makes since given his associations with Odin and Tyr. On the topic of Ragnarök and the binding of Fenrir, in my opinion it can be interpreted as a fable about what happens when you try to control the chaotic forces of nature instead of working with them. The use of gods
in fables and stories to teach lessons is extremely common so I see no reason that the Norse wouldn’t have done it as well.