I had also wondered about ‘Maru’, since it was listed with Dave Wilson (DWN), but I could find little info on it on the web. In 2017 I planted one Maru from DWN, and also a Chocolate next to it (plus other varieties).
They both bore fruit last year (2019). Below are some of my notes - I hope they shed some light on these varieties:
Chocolate: heavy flowering of both sexes; set just four fruit. 10/19/19: harvested first fruit, orange. Brown speckled inside, with narrow seeds, crunchy and sweet, good. 11/14/19: birds ate two of the three remaining fruit, remaining one was dark and gooey, with a few seeds, flesh was pure dark brown, very soft, like custard. Sweet and very good. (My wife, who is Japanese, stated that the flavor reminded her of dried persimmon in Japan - hoshigaki.)
Maru: heavy growth and bearing, thinned fruit heavily. 9/15/19 - totally green skin, but taste was good with many seeds, flecks of brown present…edible this early, but not too sweet. 10/5/19 - yellow orange skin, inside pale, no seeds, no flecks, inedibly astringent. 10/19/19: fruit now orange, brown speckled inside with small seeds, 1/2 astringent. 11/9/19: tried two fruit, both orange and starting to yield to pressure a bit. Both with seeds, brown speckled, inedibly astringent. 12/6/19: all leaves off of tree. Birds have destroyed all but 6 fruit. Most have softened. Picked the softest and it had seeds, brown speckles, and was semi-soft and very sweet, with a faint touch of spice. We had several nights in the upper 30s previously. 12/12/19: all remaining fruits destroyed by birds, except for one. All orange and semi-firm. Was not pollinated, was all orange, no brown, no seeds. Taste was very sweet and very astringent at the same time…odd and inedible. Froze the remaining portion of the fruit overnight, then defrosted it in the fridge overnight…now edible, sweet with a tinge of astringency.