Moola means “root”. Moola dasa shows the root cause of the events. It is the link between the events of current life and the past life (which is the root cause of events). At the time of Varahamihira and Kalyana Verma, this was a very popular dasa system.
If a planet shows sins in past life (shashtyamsa, D-60), his Moola dasa in this life may give punishment for those sins. If a planet shows learning in a specialized subject in past life, the native may learn that subject relatively easily in that planet’s Moola dasa in this life. And so on.
This is a very sacred dasa and should not be abused.
Rama found exile by kind Dasharatha
In Mool dasha of Mars Dashratha killed Shrwan Kumar,and in results of Dasha Ketu of Rama exiled by the helps of kaikei.Idea from Manthara the maid of Kaikei.Here maid is supporter and act like Ketu.