Which is the most metallic element amongst $\text{Li, K, Mg, C, Al}$, and $\text{S}$?

Metallic character generally increases as we move down a group in the periodic table and decreases as we move from left to right across a period. Among the elements given:

- Lithium (Li) is a metal but has less metallic character compared to potassium.
- Magnesium (Mg) is also a metal and has more metallic character than lithium.
- Carbon (C) is a non-metal and does not exhibit metallic character.
- Aluminum (Al) is a metal but has less metallic character than magnesium.
- Sulfur (S) is a non-metal and does not exhibit metallic character.

Potassium (K) is located in Group 1 (alkali metals) of the periodic table, which is known for its strong metallic character. Therefore, potassium (K) is the most metallic element among the given options.
Hence, the most metallic element among Li, K, Mg, C, Al, and S is potassium (K).