Erikson announced both trilogies before wrapping up the Malazan series in 2011 with The Crippled God. The Kharkanas Trilogy is set 300,000 years or so before the main Malazan sequence and details the backstory of the three Tiste races (Andii, Liosan and Edur). Erikson released Forge of Darkness to a generally warm reception in 2012, but took four years to release the follow-up, Fall of Light (2016). On release, the novel got a mixed (but leaning towards lukewarm) reception from readers.
Erikson has also worked on other novels in the meantime, writing three Betty comedic space opera novels and a stand-alone SF work, Rejoice, A Knife to the Heart, which will be released in late 2018. It was assumed that the final Kharkanas novel, Walk in Shadow, would also be released in 2018 or 2019.
Now, according to Erikson, he has put Walk in Shadow on hold and will be starting work shortly on The God is Not Willing, the first novel in the Toblakai Trilogy. This trilogy will catch up on the adventures of Karsa Orlong shortly after the events of The Crippled God and - it is believed - will see him return home to his people to rouse them in a crusade against "civilisation". It is likely that this trilogy will also catch up on at least some of the situation in other parts of the world following the events of the Malazan Book of the Fallen and Ian Esslemont's Malazan Empire books.
This news is startling, since Erikson has formerly been one of the fastest, hardest-working and most reliable authors in the fantasy canon. However, he clearly struggled with Fall of Light (which took more than three times as long to write as any of his previous books of comparable size), so this move may help recharge the creative batteries.
It's also good news for fans: the deep backhistory of the Tiste is fascinating to some fans, but many of the main series fans seemed much more excited about the Karsa Orlong saga, expanding as it will on a fan-favourite character from previous books.
No publication date is set for the first Toblakai novel, but hopefully we will see it this side of 2020.
ETA: From Steven Erikson:
Status Update: Completing the third and final Willful Child novel, The Search For Spark. Then it's onward to the first Karsa Orlong novel (what about the third Kharkanas novel? On hold). Thanks everyone for your kind greetings.
Hmm, okay. I've made a point of never dissembling to my readers so why start now? The reasons for this decision (delaying Walk in Shadow) are varied: the basic situation is as follows. For reasons unknown to me, my agent or my publishers, DoD and FoL have tanked in terms of sales. I wasn't even aware of that until we started marketing the First Contact novel, RKH, but when the details came out it took the wind out of my sails (putting it mildly). Now, if it was a matter of the style I employed for the Kharkanas trilogy turning readers off, then the sales of FoD should have been decent, only to then fall off for FoL. But that wasn't the case. Strangely, the Book of the Fallen series remains strong in terms of sales. Was it because it was a prequel? Possibly. Did FoD come too soon after TCG? Maybe. Or is there some kind of reader-fatigue going on? Could be. One theory I've been considering is a more general wariness among fantasy fans regarding trilogies and series -- having been burned by other authors waiting for books, are readers just holding back until the trilogy is done, before buying in? But then, Dancer's Lament sold brilliantly (and it too is a prequel). Anyway, the upshot is, given what we perceive as considerable enthusiasm for the Karsa trilogy, we decided to jump right in. The story picks up four or five years after the ten book series, so there'll be plenty of room to explore the fall-out, and room for favourite characters to make an appearance beyond Karsa himself. I do remain committed to writing Walk in Shadow and humbly apologize for you (few?) readers eagerly awaiting that novel.
Thanks so much for all your comments and encouragement. To those of you waiting for the trilogy to finish before buying, no need to apologize. Waiting for books sucks. Personally, I wish FoL hadn't taken three years to write. That alone is a long wait for any reader. I think what's made the Kharkanas trilogy so fragile for me is that it was always a risky proposition, in terms of tone, atmosphere and writing style. It's dense stuff, and while the style is seductive (for me) it's also one that requires a certain frame of mind. I wasn't aware of how vulnerable that frame of mind was until it got hammered. It may well turn out that after the first Karsa novel (working title: The God is not Willing), I'll head straight back to Walk in Shadow. Sometimes momentum is all one needs.