Final answer:
Macduff is the character who is suitable to be king and showed loyalty to Scotland by defeating the usurper Macbeth, thus truly demonstrating his allegiance and commitment to justice.
Step-by-step explanation:
The character Macduff in William Shakespeare’s play Macbeth is depicted as a figure old enough and possibly suitable to be king, and he demonstrates his loyalty to Scotland by ultimately defeating the tyrant Macbeth. While the other characters such as Duncan, Macbeth, and Banquo exhibit certain qualities or perform actions that also display loyalty to the kingdom, it is Macduff who takes the decisive action against the betrayal and regicide committed by Macbeth. Macduff's actions reinforce the values of justice and retribution in opposition to Macbeth's treachery.