In exchange, he would make the Flame Spirit of the Dusk Fire awaken ahead of time.
This was a profitable deal for both of them. Lin Yun needed the Dusk Fire to open a fertile plane, while Osul urgently needed the Dusk Fire's Flame Spirit to awaken ahead of time. Thus, the two hit it off and reached a deal in the carriage.
To be honest, Lin Yun hoped to have his own Flame Spirit.
Of Noscent's six great Magic Spirits, the Flame Spirit was the one with the most uses, especially an Upper Rank one, which would be almost omnipotent. Not only did it have a formidable fighting strength, but it could also improve an alchemist's level of alchemy by one whole rank. Naturally, a Flame Spirit of such level was rarely seen. Even the Dusk Fire in Osul's hands was only a High Rank Flame Spirit.