Which is the most caloric, edible, single ingredient by weight?
Your question goes near the  answer. As you can read on those nifty tables on products, calories come from mainly three sources: Fats, sugars and protein. There are also fibres, alcohol (that are not counted as carbs)  like ethanol and organic acids but the first three is packed with them.
So fat have 9 kcal/g, carbs 4kcal/g and proteins also 4 kcal/g (ethanol have 7 kcal/g but you can't consume it in large quantity like fat).
And from simple math you can deduce that clean fat, like olive oil, is the most caloric, edible ingredient".  

PS. Wolfram made a slight change to your question changing the "100 grams" to "107 grams" so that's why it's not "900 kcal/100 g"

Edit: I think the kcal of 1 gram of fat is not exactly 9. It may be around 9,0132 or something like that. That's why WA recalculate the amount and round up, and that's why lard seems to have more. Generally we say that fat is 9cal/gram 

Lard can be considered "cleaner" fat as it is processed fat. So it's not contaminated with all those vitamins and micro and macro elements like olive oil.