Throw kunai always uses the element of the equipped kunai. Exploding kunai, however, always uses your endow. You can use 9 earth charms instead of 10 to get an attack boost and still do fire property damage (or neutral) with exploding kunai, using either fire converters/endow (or nothing).
Woops was clicking Reply and gave you a +1, but it takes over Kunai Element. That's why its popular to use Fire Kunai + Earth Charms on Earth Property monsters.
Edited by Jaye, 08 February 2013 - 08:35 AM.