Christopher Jhonsson announced that he will quit singing in a email sent to Therion's website. He explains:

"As was announced on the Metal Mania festivals, I am going to retire from vocals. The reasons for this are two. One is that I feel it's not fun to sing anymore (even though I have enjoyed playing the old songs on guitar), the voice is getting weaker over the years and I experienced problems at the end of the US/Canada tour. The problem isn't only getting older, but rather that we basically never rehearse as a band and therefore I don't keep my throat "warm". It simply doesn't work to not sing for half a year and then go on tour for 2 months and shout every evening. It used to work when I was younger, but now I feel it's not comfortable anymore and when it doesn't feel right, it's definatly time to stop.
The second reason is that we anyway would like to stop playing old songs. By old I mean Lepaca Klifffoth and older. We are now working on our 13:th studio album and it is getting harder and harder to choose which songs to play live. The number of "classics" - songs that we more or less must play - is growing all the time and we don't want to end up like one of those bands where you know beforehand 95% for sure what songs that are going to be played. We want to be able to have space to play a couple of unexpected songs each new tour.
We of course realize that many fans will miss those brutal songs, but we are convinced that those fans also will prefer to hear something new each time from the Theli album and onwards.
Besides old songs, this will have an effect on the choice on some newer songs. For example, I'd normally sing in To Mega Therion, Invocation of Naamah, In The Desert Of Set and Typhon. I guess I in normal cases seldomly have to sing in To Mega Therion anyway - good crowds tends to do that for me!
Typhon would anyway not be on the set list on the next tour, there's so many songs we haven't played from that album. Personally I would rather do An Arrow From The Sun and the title track Lemuria next time.
As for Desert Of Set I guess we're not gonna play it and regarding Invocation Of Naamah, we might not play it or we could experiment with Mats doing some harsher type of voice on my parts, he's a pretty flexible singer as you might know by now (and he has said he don't have any principles against doing some growling type of vocals as long as it's just some few parts). So time shall tell what happens around that."

Source:	megatherion.com
Band profile:	Therion