Touched by darkness

What would be the correct form of the Latin verb Tangere when translating the following into Latin?
I have also found in my Collins Latin Dictionary that one should use the preposition a (ab) and the ablative form of the subject.
"a tenebris"
"touched by darkness"
 

AoM

nulli numeri

  • Civis Illustris

What's the subject?
 

AoM

nulli numeri

  • Civis Illustris

tenebris tangor
 
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