Lewis Snart

Lewis Snart is the deceased father of Leonard and Lisa Snart. Lewis was once an officer of the Central City Police Department. Lewis is nicknamed Colonel Cold by fans.

Raising Leonard and Lisa
Lewis was a corrupt police officer who took his anger out on his children until he was sent to prison for larceny, armed robbery, aggravated assault, and assault with a deadly weapon. It was practically Leonard who raised Lisa all by himself despite the fact that their grandmother was taking care of them while Lewis was in jail.

Heist with Leonard Snart
Years later, Lewis left Iron Heights. Lewis kidnapped his son and injected his daughter with thermite. Lewis threatened to kill Lisa unless Leonard helped him. When the Flash came to "rescue" Leonard, Lewis was surprised to see Leonard taking down the Flash since he didn't think his son had it in him.

While planning a robbery, Lewis killed David Rutenberg who was being rude to his son. Barry Allen infiltrated the Lewis' team by pretending to be a tech guy named Sam. Lewis was doubtful at first due to Barry's youthful appearance but Leonard vouched for Barry by telling his father that Barry helped him steal a diamond a few years ago.

Lewis, Leonard, and Barry posed as janitors. When their ID badges were failing, Lewis prepared to pull a gun to murder the two security guards. Fortunately, Barry figured another way to pass them without having anyone get killed. When they arrive on the twenty-seventh floor, they spotted two armed security guards. Leonard and Lewis argued as Lewis was wrong about the timing.

After Barry got the two security guards out of the way behind their backs and Lewis had him breach the security code. Lewis then shot Barry after getting the job done (Barry survived that because he was able to catch the bullet fired at him and faked his own death). When Leonard and Lewis arrived at the vault, Leonard froze the lasers and Lewis went to pick the lock. Lewis was told they had 125 seconds before the security system defrosts. After they obtained the diamonds, the sirens went off and as they escaped, they were intervened by Barry who switched into Flash. Lewis ordered Leonard to kill Flash and wanted him to stay dead like last time. Fortunately, Cisco was able to isolate the thermites from Lisa and Leonard killed Lewis after Flash broke the news to him.

Personality
Lewis Snart is:

-A sociopath since he doesn't care who gets killed unlike his son Leonard like when he was willing to kill the security guards with no guilt. Lewis even killed Barry when he was posing as a tech guy for no reason at all.

-Selfish since he was willing to kill his own daughter if his own son didn't cooperate just so he could steal some diamonds to become rich. Lewis even physically abused Lisa and Leonard when they were children just to teach them "lessons".

-He's arrogant like when he frequently ignored Leonard's advice about timing and contingencies despite the fact that Leonard had more experience in thievery.

-Lewis doesn't seem to care about his children since he hit Lisa with a beer bottle when she was young and planted a bomb in Lisa's head just to force his son to cooperate with him. Unfortunately, Leonard executed him without any second thoughts once he learned Cisco removed the bomb from Lisa.

Trivia
-He's nicknamed Colonel Cold not by Cisco, but by many fans.

-He was portrayed by Canadian actor Micheal Ironside, who played Lois Lane's father General Sam Lane in Smallville.