Tolfdir

"Good to see Skyrim still has such fine people. You give an old man hope."

- Tolfdir to the Dragonborn.

Tolfdir is an eldery Nord mage in The Elder Scrolls V:  Skyrim, who resides in the College of Winterhold. He is a master alteration instructor and later Master Wizard of the college following Mirebelle Ervine's death in the College's questline. Thoughout the college's questline, he acts as the primary mentor of the Dragonborn, often assisting them at various points.

Personality
Tolfdir is an elderly,  but nonetheless masterful wizard, he is very helpful and friendly towards all member of the College and is never arrogant or abuses his powers. He is however a bit absent-minded, as he regularly misplaces his alembic.

First Lessons
Tolfdir is the first instructor the Dragonborn meets, as he teaches the new students about defensive magic. He has the Dragonborn demonstrate in front of Onmund, Brelyna Maryon, and J'zargo how to properly cast wards in case of conflict. Afterwards, he instructs all the students to meet him at the Nordic site Saathal for an excavation study.

Under Saathal
At Saathal, Tolfdir assigns the Dragonborn to assist another College member to collect various enchanted items located across the site, upon finding an amulet, the Dragonborn gets trapped inside the room they discovered the item inside, Tolfdir instructs the Dragonborn to put on the amulet to see if it has any effect, to which it reveal a secret passageway within the site. Toldfir, alongside the Dragonborn travel inside the secret passageway, where the latter learns from a Psijic Monk that a set of dangerous chain of events has began and can't be stopped. The Dragonborn tells Tolfdir (who is unaware of the event) what just happened. The two then continued into a larger room and confront and defeat a group of Daugr, before Tolfdir decides to stay back temporarily to learn more about the acient sarcophagi.

After proceeding through a considerable portion of the following section of Saathal, Tolfdir rejoins the Dragonborn as they find the Eye of Magnus inside the burial site. Tolfdir instructs the Dragonborn to return to the college and inform the Arch Mage of the discovery.

The Staff and Eye of Magnus
After learning more about the Eye of Magnus and its potential power, and that Arcano killed the Arch Mage to have no opposition to exploit the Eye's power, Tolfdir instructs the Dragonborn to locate the Staff of Magnus, a magical tool that can counter the destructive effects of the Eye inside the Labyrithian.

Upon returning from the site, Tolfdir informs that Mirabelle Ervine has been killed and that they must confront Arcano with the staff to stop him from obtaining full power from the eye. Upon confronting Arcano, Toldfir is paraylzed by the Thalmor spy while the Dragonborn is forced to battle the mage on their own. Upon killing Arcano, Tolfdir recovers from his paralysis and becomes Master Wizard following the death of Mirabelle.

Epilogue
After the Eye is sealed away in an endisclosed location, anomalies caused by the arifact continue to appear across Skyrim. Tolfdir will inform the Dragonborn (who has become the Arch Mage following Savos' death) about each sighting and instructs them to locate and close off each anomal rip, suggesting they use the Staff of Magnus to do so more effectively.

He will also instruct the Dragonborn that whenever they need help with anything, he will always be available.