It appears that the speaker views winter as a powerful and formidable foe that is difficult to vanquish. If you examine the first stanza, the speaker notes that winter is 'deep-founded'. In the second stanza, winter is described as a man (perhaps a king?) who 'rear’d his sceptre o’er the world'. In classic fantasy, sceptres are often wielded with power and sometimes magic that is used to destroy.
The entire speech is pathos. it uses ethos to make points and the logos is backed up by pathos
