How to use Rigify on a Existing Armature?

Hello, I am trying to find a way to use Rigify on an already rigged character(Ripped from game).

I try to change the bones name, try to give a rig type to the respective bones but only errors are coming (there should be a 3 bone chain and so on).

I am trying to find functionality like Quick Rig addon from auto rig pro but with Rigify.

Here is the image of the armature for reference

What value do you get from the existing rig? Is the mesh already weight-painted? Do you just want Rigify’s control bones?

It seems to me that it if you’re interested in using Rigify, it may be faster to ignore the previous rig and just use Rigify’s workflow. Have you tried doing that?

I try the rigify method to generate a metarig acc. to this existing rig, now instead of using automatic weights i am trying to use the rigify generated armature but with previous weights.

trying to renaming vertex but because of lots of bones it is not working and same goes for renaming bones. Is there any solution to this?

If you want to use the Rigify armature with the previous weights, you either need to rename your vertex groups to match those in the generated Rigify armature or you need to rename the bones in the armature to match the names of your vertex groups. It’s slow-going work and if you have consistent naming, you could speed it up with a script, but that’s a bit situation-dependent.