Tom is unmerciful.
But to his family... he was an unmerciful tyrant.
I am sure that the peoples of the world are able to come together to provide alternatives to a crude system that kills and destroys everything that does not adapt to its unmerciful laws.
So I can't just kill him, or it makes me even more unmerciful.
...if you want to be a true friend to them, be honest... ...and unmerciful.
My father was brilliant, and he built this hospital but to his family... ...he was an unmerciful tyrant.
Six months of unbearable, unmerciful cold.
You have to make your reputation on being honest... and... you know, unmerciful.
Corrosion is an unmerciful enemy that wages war on all metal structures, and it will destroy an aircraft by slowly eating away at its structural integrity.