i did it by bringing eight bounce bomb+ , two large barrel bomb + , three large barrel bombs , and seven small barrel bombs (one for each bomb plus the supply ones, bounce bombs and anti-dragon bombs don't need to be exploded by small barrel bombs).
i used the weapon devil slicer and used this combo" triangle, triangle, R, triangle, R, triangle, R.
Hope this helps
Uhhhh , yeah about that hes not weak to thunder , hes weak to fire and drag. Use "Wyvern blood". That will at least repel him for ya if your on your own.