So I will give you the background of the situation im in. My players wanted to try some of the other rule books like rouge trader dark heresy etc after we were done with only war so I thought of a way to keep their players if they wanted too but still have them roll for new stats/skills etc. The solution? Being mind wiped. Why mind wipe? Bc its the GM's cheese. The way out. When your campaign is getting way to big introduce them to some forces of chaos and than just keep upscalling the campaign into a apocalyptic setting and introduce them to space marines and grey knights. Where there are daemons there are grey knights. Have them par take in a huge battle involving thousands of regiments losing a ton of ammo in shooting endless waves down and maybe even give them a tank or two or even a super heavy. Have it end in a bang where they are the heros where each time they miss a daemon goes threw the line and attacks another squad to show consequences. At the end of the battle if anybody survived the battle at the end of the day have them take part in a "honor" dinner where they are introduced to what they would like to be in life and than have them each mine wiped and induce them with false memory and ya. There ya go. You would be surprised how many groups I did this with and they all liked it.

Ehhh...

Wouldn't it effectively be the same as just...starting a new campaign in the system that they're wanting to move to when the campaign ends? Seems a little contrived for something that could be rectified by closing out the game and starting a new one.

Please note that it's very difficult to port characters between DH2/OW/BC and RT/DW/DH1, mostly due to the different system. Why not let them start new and let them discover the Impact their Characters had from the end of the campaign onwards? Or let them view the events from a different perspective?

My 2 thrones.

I have to agree with the previous two posters.

I think instead of going through that unecessary cheese-moment, have the game finish. Have them roll new characters in the new system of their choice and provide them really memorable moments to hear about the eventual fate of their old PCs. Perhaps one of them is now the Lord Marshall of a crusade - having moved up the ranks after their legendary battle-finale.

I know that one of my favorite parts about playing a multi part game (like Mass Effect for example) is the seemingly inconsequential areas where you would hear someone mention your exploits or something you had a definite hand in changing or enacting.

Give them the satisfaction of starting something new while acknowledging their past accomplishments. Hell, even bring back some of their old character's as NPCs.

As a small anectdote, in one OW game that is not going anywhere, I have an Operator that I really like. But, since I know that due to real life that game won't go on, I named a Mk. IV Commant Laspistol after that character and had one of my players find it in a DH game I am running. The pistol had his name and a rank (much higher than what it is now) stenciled into the barrel. After she looked more into it, I PM'd her the history of the pistol and its owner. Basically, I Tarantino'd the situation.