Efficient and effective character builds in Dungeons & Dragons have been a major feature since third edition, if not before then. This following example for 5th edition : How to survive a great fall (1000 meters & over) as level 2 Half Orc barbarian and still walk to tell the tale:
This is just a thought experiment, but I think I have figured out a way for my current PC, which I am basing this idea on to not die from falling off a cliff.
First, I will have to stipulate a few conditions:
1. The half orc's max hp is 20 points or over and he's at full health.
2. He still have at least 1 rage usage left.
3. He still has his Relentless Endurance racial trait available to use.
4. He is unrestrained and is free to do whatever he wants.
This is what we know about falling damage rules:
* According to the PHB, maximum fall damage is 20d6. Looking at the wikipedia link below, I assume that's because it reached the terminal velocity of 200mph.
* Wikipedia also says that the terminal velocity of a skydiver in a belly-to-eath (face down) position is 122mph.
So putting these two set of information together, our half orc can survive a fall in this way:
1. Get into a freefall position to achieve maximum drag. At 122mph fall rate, you can argue a case with your DM to reduce the number of damage dice accordingly. Let's say to 13d6, to round it up.
2. At 6 seconds before you touch the ground, Rage! (because rage only last 1 round if you don't attack or lose HP)
3. You hit the ground & DM rolls 13d6 for bludgeoning damage. Let's say that your DM is lucky and got all 6s for a total of 78 dmg.
4. Rage gives you resistance to bludgeoning damage, so you take only 39 damage.
5. Your hp is at -19, but since it does not reach your max HP negative, you don't die instantly.
6. Using the half orc Relentless Endurance racial trait, you drop to 1 hp instead of 0hp.
7. Walk away and sing your tale of survival against insurmountable odds.