okb1100  filed a request to merge aria2-systemd  into aria2c-daemon :
These two packages are practically doing the same thing. Also aria2-systemd package provides a broken unit file. I have to add Type= forking to the unit file to run it.
 https://aur.archlinux.org/account/okb1100/  https://aur.archlinux.org/pkgbase/aria2-systemd/  https://aur.archlinux.org/pkgbase/aria2c-daemon/
Request #16595 has been accepted by diabonas .