Consider the conjunction ども, e.g.:
- Verb Hypothetical form (仮定形) + ども
This leads me to hypothesise that the conjunction けれども (meaning "but; however; although") is built from けれ + ども.
I am unable to find a verb that is けれる. There is 蹴る though.
What is the composition of けれども? Or is it impossible to break it down further?