Mr Thackeray said the alliance with Sambhaji Brigade was ideological.
Shiv Sena president Uddhav Thackeray on Friday announced the party's alliance with the Maratha outfit Sambhaji Brigade.
The development came as the Thackeray-led party is reeling under the impact of Eknath Shinde's rebellion and the loss of power in Maharashtra.
Talking to reporters here, Mr Thackeray said the alliance with Sambhaji Brigade was ideological and forged to uphold the Constitution and also regional pride.
He slammed the BJP for not adhering to the Rashtriya Swayamsevak Sangh's (RSS) ideology and said the Sambhaji Brigade comprises people who fight for ideology.
Mr Thackeray also denied the allegation that he had called Chief Minister Eknath Shinde "contract CM".
He will be touring the state around Dussehra and is currently focusing on building the organisation, the Sena chief said.
Over the last two months, he had been contacted by many parties which had ideological affinity with the Sena and even the ones which were its polar opposite, he said.
These parties wished to come together to save regional pride and regional parties, he said.
Sambhaji Brigade chief Manoj Akhare said the organisation had formed its political wing in 2016.
The two parties have decided to come together and appoint a coordination committee for seamless functioning, he said.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)