Artemis Fowl series

2.

"When Artemis learns that his father has been kidnapped by the Russian mob, he races to the Arctic Circle to make a daring rescue where he finds an old acquaintance, Captain Holly Short, who is investigating a plot of the goblin mob." -- from cataloger.

4.

Artemis has no memory of the fairy people and has returned to his unlawful ways. In Berlin, he is preparing to steal a famous Impressionist painting from a German bank. He doesn't know that his old rival, Opal, has escaped from prison by cloning herself. She's left her double behind in jail and, now free, is exacting her revenge on all those who put her there, including Artemis. Meanwhile in the lower elements, Captain Holly Short of the LEPrechon...

6.

When the only way to save his mother's life lies with the lemurs he made extinct five years ago, Artemis turns to his fairy friends to take him back in time, where he tries to undo the damage while avoiding his dangerous younger self. Just when Artemis Fowl decided to forego criminal activity of the magical kind, his mother became gravely ill. The only way he can save her is by traveling back in time to steal the cure from the clutches of the devious...

8.

"Teenage genius Artemis Fowl and his arch rival Opal battle to the last in this eighth and final book in series"--Provided by publisher.