Comments from the Finger: Magitech Hero uses robotic armor. The Machine patron gradually makes you more machine than man. This oath makes you all machine.
Oath of the Three Laws
The Oath of the Three Laws is the only sacred oath taken posthumously. Paladins gravely injured are taken to the temple of the Gearpriests and offered the Choice: refuse the Oath and perish, or take it and become a Tech Knight. Those that accept have their minds transferred into a modified suit of magitech armor, filled with ticking clockwork, and live out the generations in command of a body of steel that is not their own.
Laws of Robotics
Because you control the form of a machine, you need to obey some of the machine's laws. Failing to do so will not cause you to fall from paladinhood, but will instead deactivate you temporarily. If you break one of the Laws of Robotics, you can neither move nor take actions for 1d4 rounds.
First Law. You may not harm an innocent sentient creature. You may not, through inaction, allow a sentient creature to come to harm.
Second Law. You must obey the orders given by the Gearpriests, except where such orders would conflict with the First Law.
Third Law. You must protect your own existence as long as such protection does not conflict with the First or Second Laws.
Oath of the Construct Spells
3rd: false life, thunderwave
5th: heat metal, spider climb
9th: protection from energy, lightning bolt
13th: dimension door, stoneskin
17th: animate objects, wall of force
Tech Knights are not born; they are created. If you suffer no catastrophe and are not offered the Choice, at 3rd level you must consult the Gearpriests to give up your organic body for a mechanical one in order to take this oath. You forfeit all benefits from your race except for known languages and ability score increases.
You are a construct, and do not need to eat, sleep, drink, or breathe. You do, however, still require the duration of a long rest each day to re-calibrate and perform minor repairs. Additionally, you are immune to necrotic and poison damage, you are immune to being poisoned, and magic can't put you to sleep. You are affected by effects which effect humanoids as well as those that effect constructs.
Finally, your body is already armored, and you cannot wear additional armor, though you may wield a shield. Your Armor Class equals 14 + your Dexterity modifier.
When you take this oath at 3rd level, you gain the following Channel Divinity option.
Emulate Upgrade. Your body is constructed from a transmutive material which can pattern after Magitech Upgrades. You may select 1 Magitech Upgrade for which you meet the prerequisites. You must expend your Channel Divinity when you complete a short or long rest in order to activate this upgrade, and you may change your upgrade selection at that time.
You are always considered to be wearing magitech armor and your magitech level is equal to your paladin level. Upgrades that cast a spell require no verbal or somatic components. If an Upgrade calls for a saving throw, it uses your Spell Save DC.
You may select an additional Magitech Upgrade at 11th level (2 upgrades), and at 20th level (3 upgrades.) These upgrades may be used as prerequisites for others.
At 7th level, you and all friendly creatures within 10 feet of you have advantage on Concentration checks.
At 18th level, the range of this aura increases to 30 feet.
At 11th level, you can select an armor fortification from below. This selection cannot be changed once made.
Energy Deflection. You have resistance to lightning damage.
Maneuverable Fibers. Your base movement speed increases by 5 feet.
Reinforced Fibers. Your Armor Class increases by 1.
Construct Sense Upgrade
At 15th level, select a construct sense upgrade from below. This selection cannot be changed once made.
Auravision. As a bonus action on your turn, you can cast detect magic without expending a spell slot. After using this ability, you must complete a short or long rest before using it again.
All-Frequency Scan. As a bonus action on your turn, you can gain truesight until the beginning of your next turn. After using this ability, you must complete a short or long rest before using it again.
Darkvision. You gain darkvision with a range of 120 feet.
Thermal Vision. Even in heavily obscured conditions, you can see the location of creatures within 30 feet that aren't constructs or undead. However, you cannot discern distinguishing details of these creatures, nor can you see what they are carrying.
Beginning at 20th level, as an action on you turn, you or one willing creature within your reach becomes immune to a spell of your choice for 1 hour. After using this ability, you cannot do so again until you finish a short or long rest.
Changelog: 11/7/15: Construct Sense Upgrade: Darkvision: Sentence was unfinished. If you already posess darkvision, its range increases to 120 feet
Emulate Upgrade: Now clarifies that you are always considered to be wearing magitech armor, and you may use your paladin level in place of a fighter level.
11/8/15: Darkvision: You gain darkvision with a range of 120 feet.
Emulate Upgrade: Now has contains the rules for save DCs and spells.
11/9/15: Magitech Upgrades no longer specify fighter level. They instead use a more class-generic magitech level.