The first merit transaction is this one: https://bitcointalk.org/index.php?topic=2818066.msg28853325#msg28853325
Merit sender: theymos.
Merit receiver: AdolfinWolf

Thank you mate for the information. Yeah, as I guess, the first merit sender is theymos as well.

-snip- the first merit sender is theymos as well since he is the first merit source.

Now, with your information above, everything makes sense and clearly enough. Thank you so much for your help.