The latest series in the Garo universe will air next year.
Rei Fujita, who portrayed Rei/ZERO in three seasons (Garo: Golden Knight, Makai Senki, and Makai no Hana) as well as the Zero miniseries, Black Blood, finished filming on the latest Garo TV series and provided the following comments:
Starting from Black Blood and now Dragon Blood, I think that now I can say that I have entered a brand new stage, together with Mr. Amemiya and the staff. It will be something I’ll treasure forever. I am positive we have created something really good. I want to thank everyone. It is a very Zero like work. It certainly belongs to the GARO universe and feels as part of it, but after all Rei Suzumura has gone through and all his development, something new and original was born. Filming may have ended but now it is time for refining details and adding effects. I look forward to what becomes in the end when we all see it on air.
The current Garo series, Makai Retsuden, will finish its broadcast in July and be followed up by a one episode special and an HD rebroadcast of the original Garo TV series from 2005-2006. The rebroadcast is expected to run through the rest of the air while Zero: Dragon Blood has been confirmed via Toukoku Shinsha for a 2017 premiere date.
Source: Touhoku Shinsha Press Release