I think you should branch out with your next character. Learn throwing and slowly sap that giant's life from a distance. That should sow the seeds of your victory.
Ah, throwing, that old chestnut. I pine for the days when it was ludicrously effective. But even though alder changes in the new version have changed it a bit, you'll still find that if you lycophyte, you willow your life as much to hastily hurled stones as you will to being spruced up in armour and elm. Especially against demons, whether they be of ash or covered in fir. So, yep, train throwing or you'll rapidly become a copse.