Gameplay design (re: storytelling)

Our current roster of characters is: 

  Rahil, who leads the characters in their expedition.  
  Vyomesh , who is the group's emotional metronome.   
  Mateel , who is the group's logician. 
  Kelechi , who is the sardonic 'critic' within the group. 
  Vritak , who is the group's 'heavy'. 

Let's look at 'damage, tanking, support' 

If we look at this organization, we want two tanks. They should be Rahil and Vritak. 
The primary damage dealers are Mateel and Kelechi. 
The healers are Rahil and Vyomesh.