Am I interpreting this correctly? 凡物只所持，不外乎三种，神念、灵气、元血。只是，一旦错了。就不知会如何了。
凡物只所持，不外乎三种，神念、灵气、元血。只是，一旦错了。就不知会如何了。

In my opinion,i translate to 凡是万物若想要控置他们，不外乎三个，神圣意念，灵魂气息，元血。只是，其中一個一旦错了。就不知会如何了。

If all things want to control them, there are only three kinds of things to be controlled
: divine ideology, spiritual aura, and primordial blood. But (we) don't know what'd happen if a mistake(at least one of three concept is in incomprehension) occurs. 

神念 means the mindset of the thing(or person,creature).

灵气 means the fourth dimension of the thing. 

元血 is the medium to communicate to the third dimension of physical body.

reference by myself