Joining the Armenian Revolutionary Federation (ARF), Tatul founded the "Dashnaktsakanner" unit of volunteers in Karabakh.

Krpeyan headed the self-defense of the sub-district Getashen-Martunashen from September 1990 until late April 1991 against Azerbaijani armed forces units and police detachments (OMON).

In the spring of 1991 the main battleground of the partisan war was the wooded hills to the north of Nagorno-Karabakh where fighters from Armenia infiltrated to Armenian inhabited villages.

The role he played wasn't limited to just fighting…[3][better source needed]Krpeyan was buried in his native village Areg, which was renamed Tatul after him.

In 2004 Rafayel Sahakian published a historical fiction book named Artsvapasht Yerkir (Eagle-worshipping Country) dedicated to him.

"Mayramut Ijav" ("The Sun Set") was composed by Ashugh Gevorg, as well as Ashot Babayan's sonata for cello and piano in 1993, were all reportedly dedicated to Tatul Krpeyan's memory.