Supernatural fans are excited to see how Misha Collins, best known for his role as Castiel, will tackle the iconic villain Harvey Dent in The CW's Gotham Knights. Given the emotional and physical depth that Collins breathed into Cas since season 4 of Supernatural, the hype is real.

However, while Castiel was innocent in many ways, the angel was also a particular font of information, especially with the divine. While Team Free Will didn't seem to know if Castiel was the heart or the brawn of the group, he had a brain that could comprehend the incomprehensible along with a particular way of sharing his thousands of years of knowledge.

It's Simple Really

"It's A Simple Matter Of Blocking Out Certain Subsonic Frequencies. I Could Draw You A Diagram If You Want."

In a hilarious episode where the Angel of Thursday decides to become a hunter, Castiel shows how invaluable he is to Team Free Will. Whether he's interrogating a cat or sniffing a dead body for signs of EMF, he makes light work of hunts.

RELATED: 10 Best Castiel Episodes In Supernatural, According To Reddit

When Castiel explains that he has turned off "Angel Radio", Sam, Dean, and viewers are reminded just how intelligent the resident angel is - when it hasn't got to do with pop culture or social cues. He has capabilities and intricate knowledge of existence on a molecular level. While he doesn't know what Looney Tunes is, Castiel knows what he's talking about with infrasonics.

Make Love Not War

"We're Each A Fragment Of Total Perception - Just One Compartment In That Dragonfly Eye Of Group Mind."

In Season 5's episode 'The End', Zachariah sends Dean five years into the future to show him what could happen if he keeps saying "No" to Michael. While this is one of the best Dean episodes in Supernatural, Endverse!Castiel can't help but stand out. Without his powers, Castiel becomes a hedonistic soldier preoccupied with decadence, orgies, and drugs.

This quote is beautifully and intelligently expressed to show how one's perception differs from another's - particularly from an angel who shares a connection with every angel in existence. However, this quote becomes much funnier when we learn the "love guru" is not giving a sermon on philosophy but about sharing group minds and group sex with these women.

Know Your Audience

"The Answer To Your Question Can Best Be Expressed As A Series Of Partial Differential Equations."

Image of Castiel looking pensive

Castiel often finds himself having to 'dumb down' his explanations of time travel, Angel Radio, and flying to the Winchesters who don't understand celestial physics. When Castiel is planning to send Sam and Dean back in time to 1861, he reveals that they will only have 24 hours to find the phoenix that Samuel Colt wrote about in his diary.

Unfortunately, Castiel never got to show his comprehension of quantum mechanics and general relativity as Bobby reminds Castiel to "aim lower" when talking to those with little understanding of time-travel physics. Instead, he explains that the further back he sends them, the harder it becomes to retrieve them. Often because of the inability to understand social etiquette or Dean's references, Castiel's vast intelligence is forgotten or ignored entirely.

Angelic Invisibility Cloak

"An Enochian Sigil. It'll Hide You From Every Angel In Creation, Including Lucifer... I Carved It Into Your Ribs."

Shortly after being resurrected by God (or the prophet Chuck as he was known then), Castiel rescues the Winchesters from Zachariah's wrath cementing his position in Team Free Will as a true hero. And in one of Castiel's most brilliant ideas in the series, he decides to carve Enochian sigils into Sam and Dean's ribs to hide them from Angels - particularly Michael and Lucifer.

The carvings keep them hidden from all angels meaning that when they wanted Castiel to join them, they then had to call him first. While he had trouble using a phone at first, his genius is irrefutable. Carving it into the Winchester's ribs, while painful, brilliantly solves the tattoo problem in which if a tattoo seal is broken (by an injury), the sigils would stop working.

As Sane As The Next Man - Or Angel

"I'm Perfectly Sane. But Then 94% Of Psychotics Think They're Perfectly Sane, So I Guess We'd Have To Ask Ourselves 'What Is Sane?'"

Castiel did not have an easy time after Team Free Will managed to divert the Apocalypse. He was fighting an angelic civil war against Raphael, he consumed Leviathans from Purgatory, took on Sam's Cage trauma, and was then banished to Purgatory with Dean when they killed Dick Roman, leader of the leviathans.

RELATED: 8 Times We Felt Bad For Castiel In Supernatural

"Crazy Castiel" took on Sam's mental trauma from his time in the Cage with Lucifer and became a very different character. It seems to land in Purgatory reset Castiel's mind but that didn't stop him from abandoning Dean. In response to Dean asking Castiel how he feels, Castiel philosophically wanders and begs the question "What is sane?". It is a brilliant question that no one has the answer to.

Ghost Writer

"You Never Learned How To Tell A Good Story." "But You Did."

Image of Castiel in Metatron's study

When going against Metatron, one of the most manipulative and intelligent Supernatural villains, Castiel knows brute strength just won't cut it when Metatron has a mass of angels blindly following him. Castiel understands that clever tactics and a thorough strategy are needed to truly beat the Scribe of God - unfortunately, that means sending Dean into a battle that resulted in his death and demonic transformation.

Once Castiel destroys the Angel Tablet, Metatron finds him and villainously monologues his evil victories over Team Free Will and sheep-like angels. What Metatron doesn't realize is that Castiel is broadcasting his speech over his own Angel Radio kit, letting all of Angelkind know what he thinks of them. It is such a genius tactic to defeat an angel so obsessed with good storytelling by letting him tell the angels the real story.

Food For Thought

"It's As If We're In Every Biggerson's At Once - Trapped In A Quantum Superstition."

Image of Castiel sitting alone at a table in Biggerson's in Pittsburgh, Pennsylvania

Another reminder that Castiel began the show as a warrior, he's an excellent tactician. He led Heaven's armies, commanded his legion, and he gave it all up for the Winchesters. When he escaped Naomi's mind control, Castiel took the Angel Tablet with him.

Given that Castiel (as well as other angels) has a keen grasp on quantum mechanics, he knew full well how to give the angels the slip. By jumping from one Biggerson's to another, the angels and Castiel are simultaneously in every Biggerson's and none of them - but their paths don't cross. Castiel's genius came up with a tactic that Naomi could only solve with mass murder to get his attention.

Curiouser and Curiouser

"It Does Present A Curious Curl In The Metaphysics Doesn't It? If You Kill A Monster In Monster Heaven, Where Does It Go?"

Castiel and Dean spent a year in Purgatory after killing Dick Roman.  During their time in the monster afterlife, Dean, Benny, and Castiel seemingly killed dozens of monsters. Curiously as they are in Purgatory, the creatures are already dead but were able to be killed again.

Castiel is the only one to voice the viewers' thoughts on this by questioning this metaphysical flaw and wondering where these monsters are then sent to - Monster Hell? The Empty? As a celestial being, Castiel's very existence is tied in with philosophy but just because he has experiential knowledge of the fabric of the universe doesn't mean he knows everything.

Sleeping Beauty

"I'm Awake. And I Will Stay Awake And I Will Keep You Awake Until We Both Go Insane. I Will Fight You... For Eternity... Release Me."

By season 13, the Winchesters had truly rubbed off on Castiel. So much so, that Castiel even adopts his wayward orphan and annoys a cosmic entity so much that it brought him back to life. After being killed by Lucifer, Castiel is sent to The Empty but is woken up by Jack's Nephilim powers.

RELATED: 5 Times Castiel Betrayed Dean (& 5 Times He Saved Him) In Supernatural

The void where dead angels and demons are sent to is guarded by an unnamed deity that is as old as Chuck and Amara. Unhappy to be awakened, the being tries everything to force the angel back to sleep. Castiel uses this to coerce the entity into resurrecting him. A brilliant tactic that invariably results in the being's hatred of Castiel and unfortunately ends in his death and Dean's survival in one of the show's final episodes.

What's Up Doc?

"The Bird Represents God, And The Coyote Is Man Endlessly Chasing The Divine But Never Able To Catch Him."

Castiel going to interrogate the cat

In a case involving cartoons showcasing one of Castiel's best moments, the angel finds himself needing to watch Looney Tunes to understand the rules of the genre - anvils fall from the sky landing on the giant X, black holes drawn on walls become doorways and hearts can jump out of people's chests at the sight of their loves.

Castiel studies Wile E. Coyote and the Road Runner and rather than just finding the slapstick humor funny, he also finds a deeper layer in the animated shorts. He compares them to humanity's elaborate plans to reach God that inevitably fail and indeed finds it hilarious. It also proves that Castiel and other angels exist on another wavelength to humans in which they have a more advanced understanding of everything from philosophy to physics.

NEXT: 10 Quotes From Supernatural That Prove Sam Winchester Is A Genius