Of the most recent, We have over 10 Character confirmations
Playable Characters
Ieyasu Tokugawa
Voiced by Toru Okawa
Tadakatsu Honda
(no voice)
Keiji Maeda
Voiced by Masakazu Morita
Hideaki Kobayakawa
Voiced by Jun Fukuyama
Tenkai
Voiced by Sho Hayami
Kanbe Kuroda
Voiced by Rikiya Koyama
Motochika Chosokabe
Voiced by Ryuzou Ishino
Magoichi Saika (Saica)
Voiced by Sayaka Ohara
Tsuruhime
Voiced by Ami Koshimizu
Matsu (Maeda)
Voiced by Yuhko Kaida
Toshiie Maeda
Voiced by Tomohiro Tsuboi
Not all character plots have been revealed yet. However, some clues have appeared in trailers. Akechi seems to be suffering some sort of identity crisis. (This may explain why Tenkai is playable but Akechi is not) Kanbei may be trying to reunite with Mataemon Goto, While Ieyasu seems to be questioning his reasons for joining the Toyotomi. Much like in the anime, Keiji appears to be seeking out Toyotomi (going as far as crying) The bond between Ieyasu and Motochika (The one which Motochika swears Ieyasu broke in Sengoku BASARA 3) is formed. Hopefully more details to follow soon.
PART 2 will contain information about the newest features to the game.
LINKS:
Capcom's official Sengoku BASARA 4 webpage - http://www.capcom.co.jp/BASARA4/