Edwin death #1
I suppose my answer depends on who you are,
"I have forgotten who I am. I was imprisoned here long ago because I was thought to be dangerous."
who the master is,
"The master of this realm is Strahd Von Zarovich. No soul may enter or leave, except by his will."
where this is,
"This realm is Barovia, a demi-plane of sequestered lands, set apart to punish Strahd. This place is known as the Amber Temple and was here long before Strahd or Barovia existed."
who it is I am killing,
"To survive in Barovia is to kill. It matters not to me. If the person you kill has a soul, it will be sent to me."
the purpose to which these souls shall be put,
"I do not know. Some may go back with a task or tasks from me. Some may wish to end thier suffering in this land and I will consume them. Whether they serve me or not will be left their choice, just as it is with you."
the impact of their being sent to you on my soul,
"Your soul will be sent back to your body. Souls stay in this realm, they do not go to meet their gods. Yours is a new soul. The others here are old and worn. They all look the same to me. Yours will look like them eventually."
and the manner of the sending
"When you unmoor a soul, it will come to me, and the act will fortify you." (When something you do brings a creature [with a soul] to zero HP, you will gain temporary HP equal to your level).
*Point of information, we will be going with 0hp = death for mooks, player rules for important npcs. You can choose to knockout at 0hp if feasible for that situation.*