| Wagram said: The only covenant that sounds really annoying is the Blade of the Darkmoon. I'm assuming I have to invade and kill 10 people. That's probably going to take forever. |
Once you get to the final area of the game, and if you're around SL 80 - 90, you can find a lot of PVP going there. It's pretty easy to rack up 10 Souvenirs of Reprisal in that place, I was able to get 6 in less than an hour.
The other alternative is farming them off the Harpies in the Painted World of Aramis....and that really takes forever 
Current PC Build
CPU - i7 8700K 3.7 GHz (4.7 GHz turbo) 6 cores OC'd to 5.2 GHz with Watercooling (Hydro Series H110i) | MB - Gigabyte Z370 HD3P ATX | Gigabyte GTX 1080ti Gaming OC BLACK 11G (1657 MHz Boost Core / 11010 MHz Memory) | RAM - Corsair DIMM 32GB DDR4, 2400 MHz | PSU - Corsair CX650M (80+ Bronze) 650W | Audio - Asus Essence STX II 7.1 | Monitor - Samsung U28E590D 4K UHD, Freesync, 1 ms, 60 Hz, 28"
