Jonathan Allen is a fine metal drummer who played a.o. in Sadus, Testament and Dragonlord. Hailing from San Fransico, this latter band was initially called Dragonheart but changed name in 2000.
Jon Allen replaced John Tempesta when the latter decided to leave Testament for Helmet. However, due to personal reasons (a seriously ill daughter) Allen soon had to quit. He was replaced by Paul Bostaph (known from Slayer).
Allen's primary musical influences are early Black Sabbath, Rush & Iron Maiden. If you take the heaviness of Bill Ward, the precision of Neil Peart and the speed of Clive Burr; those three elements make a lot of the style in Sadus drumming.