Offensive tree

Summoner's Wrath : Removes 10 of Armor and Magic Resist of an enemy with Exhaust, great for focusing in team fights.

Brute Force : Three attack damage is not anything noticable, but its helpful for proceeding down the offense tree.

Alacrity : Useful for landing consecutive lasthits and for charging up Aegis Protection faster and for of your Heartseeker Strike passive.

Weapon Expertise : It synergises nicely with his abilities.

Deadliness : More attack damage.

Lethality : Very good with Heartseeker Strike passive.

Vampirism : The lifesteal gives you some sustain early game

Sunder : It synergises nicely with his abilities.

Executioner : Extra damage against wounded enemies. Works awesomely well with the passive of Heartseeker Strike.

Defence tree

Hardiness : Some extra armor to withstand early game harassment and win those crucial exchanges.

Resistance : Provides some defence against Ap characters early on.

Durability : Expands your health pool by 108.

Veteran's Scars : Works nicely early game and helps a lot when going toe to toe.

Marks

Greater Mark of Attack Damage: Very strong runes early game. Nocturne already has Black Cleaver so you don´t need more armor penetration, in fact you already have some from the masteries.

Seals

Greater Seal of Armor: By far the best choice for seals in my opinion. The extra armor early on is a great asset for winning your lane and withstand early pokes.

Greater Seal of Replenishment: These will make you able to use your Spear Shot more often and avoid mana starvation in general, so you can have some ranged farm.

Gliphs


Greater Glyph of Scaling Magic Resist: Magic damage becomes more and more threatening as the enemy Ap carries get more levels on their spells. So this gives you some defence against them.

Greater Glyph of Scaling Cooldown Reduction: Pantheon benefits greatly from cooldown reduction in general because most of his damage is produced by his abilities.

Quintessences

Greater Quintessence of Critical Damage: These runes are really bad in most champion, but in Pantheon, not only you will benefict from Heartseeker Strike passive but you will also from the 25% critical strike from Infinity Edge. If you don't like these runes you can use Greater Quintessence of Attack Damage

aegis protection
After attacking or casting spells 4 times, Pantheon will block the next normal attack that deals more than 40 damage to him.
Pantheons passive provides protection against hight impact hits. It doesn't block spellbased abilities.
You are able to Block:
-Siege creep hits.
-Turret hits.
- Parrrley.
- Mystic Shot.
- Decisive Strike.(You block the damage,but still get silenced).

spear shot

Pantheon hurls his spear at an opponent, dealing 65 / 105 / 145 / 185 / 225 + 140% of his bonus attack in physical damage. If Heartseeker Strike has been leveled up once, Spear Shot will deal 150% damage against opponents whose current health is below 15% of their max health.

This is your poke spell. Its low manacost and good range makes it exellent for harrassment and lane control. Its trustworthy and gets the job done.

aegis of zeonia

Pantheon leaps at the target enemy champion and deals 50 / 75 / 100 / 125 / 150 (+100% of ability power) magic damage and stuns them for 1 second. Pantheon also instantly refreshes his Aegis Protection.

This spell is crucial for Pantheon as is closes the distance between you and your target. Along with that it provides 1 second stun and trigers your passive.

heartseeker strike

Passive: Pantheon gains 100% critical strike chance against targets below 15% of their max health.
Active: Pantheon channels for 0.75 seconds and deals 3 swift strikes in a cone in front of him. Each strike deals 13 / 23 / 33 / 43 / 53 (+60% bonus attack damage) physical damage, and they deal double damage to champions.

This is your most powerful spell. If maxed first it can devastate your target. Combine it with Aegis of Zeonia for better results. If the enemy team does not have many stuns or interrups this is the way to go.

grand skyfall

Pantheon gathers his strength channeling for 2 seconds and then leaps high in to the air, crashing down at the target area 1.5 seconds later. Deals 400 / 700 / 1000 (+100% of ability power) magic damage to units at the center (down to 50% at the edge) and slows them by 35% for 1 second. If the channeling is cancelled, the cooldown is reduced to 10 seconds. Ignores spell immunity buffs (like Morgana's Black Shield).

Your personal damaging Teleport. It can provide many kills early game if used properly. Always keep in mind that it needs 3.5 seconds for you to jump in the selected location. Its easy to fail with that spell and takes time and practice to master. But its really enjoyable coming out of nowhere.