“kraken” is the “name” of the API, not the channel to lookup.
v5/kraken is deprecated you should use new API/helix
Bio: Reference | Twitch Developers
Follow count: Reference | Twitch Developers
Sub Count: Reference | Twitch Developers (load all pages and count yourself)
If you intend to use the Deprecated v5:
Then if you have the users oAuth token you call, for bio you would call the channels API:
https://api.twitch.tv/kraken/channel
if you don’t have the users oAuth you call
https://api.twitch.tv/kraken/channels/CHANNELID
And substitute in the channel ID (not user name)