If wearing this item does apply all runes, does plus percent damage fire or physical on the item also happen? I note that the item shows 20 percent Fire increase and one of the runes is a fire one. Another question would be if you select a rune, do all the others still happen?
The elemental damage on the bracers is not related to the legendary power which gives you all the WotB runes.
The elemental damage is always in effect as a passive bonus, not only when you have WotB running.
The only reason to select a specific WotB rune while wearing these bracers, is for cosmetic purposes. Each rune turns him into a different coloured Super Sayan. You will have all the runes abilities regardless of which one you pick.
Thanks - great answer.