- Roy is heavier than Abhishek.
- Both Roy and Abhishek are taller and heavier than Das.
Therefore, Das is shorter and lighter than both Roy and Abhishek.
- Vivek is lighter than Abhishek.
- Ranjan is heavier than Das but shorter than Das.
- Given that Roy is heavier than Das, the statements imply Abhishek is taller than Roy.
- Vivek is heavier than Ranjan.
- Das is lighter than Roy and Abhishek.
- Ranjan is heavier than Das.
- Vivek is lighter than Abhishek but still heavier than Das (since Das is the lightest overall).
\[ \boxed{\text{Das}} \]