1. To start -Maumpisahan: from the root word "umpisa"
2. "e" could have been a shortcut to "ay" in this sentence.
But it is used in many different ways
but the use in the sentence may seem
"that" [or] "is"
Sample uses of 'e'
1. E bakit? (used as "BUT": "BUT WHY?")
2. e ewan ko.. (used as "oh": "Oh, I don't know")
3. Ako'y nagutom kahapon e kumain nmn ako ng marami. (used as "BUT")
4. Kahit mabuti adhikain nya e masama naman nakapaligid sa kanya (used as "however")
5. Masamang masama ang kanyang pakiramdam e hindi na nga sya makatayo
(used as "THAT": He has a nasty stomach bug that he couldn't get up")
This is overdue, but I think I still need to answer it for information purposes.
Have a great time!