Did he introduce a lad into evil ways? (7)

I believe the answer is:
saladin
'did he introduce a' is the definition.
The definition suggests a singular noun which matches the answer.
'lad into evil ways?' is the wordplay.
'into' is an insertion indicator.
'evil ways?' becomes 'sain' (I can't explain this - if you can you should give a lot more credence to this answer).
'lad' going inside 'sain' is 'SALADIN'.
Can you help me to learn more?
(Other definitions for saladin that I've seen before include "Muslim warrior" , "Crusade warrior" , "Enemy of Richard I in the Crusades" , "Crusade foe of Richard I" , "Richard the Lionheart's enemy" .)
