Kaho, Minamo Historian — ruling 1

If an effect takes a card Kaho exiled out of the exile zone, then you can't use Kaho's ability to cast that card.

Kaho, Minamo Historian — ruling 2

If another player gains control of Kaho, that player may cast any of the cards exiled with Kaho's ability.

Kaho, Minamo Historian — ruling 3

Kaho's activated ability refers only to cards exiled by its triggered ability. If another effect exiled the cards, you won't be able to use Kaho to cast those cards.

Kaho, Minamo Historian : règles, fonctionnement et interactions (MTG)

Kaho, Minamo Historian is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

When Kaho enters, search your library for up to three instant cards, exile them, then shuffle. , : You may cast a spell with mana value X from among cards exiled with Kaho without paying its mana cost.

How it works : Kaho, Minamo Historian

Original English text — Wizards of the Coast / Scryfall

#1June 1, 2005· Wizards of the Coast
If an effect takes a card Kaho exiled out of the exile zone, then you can't use Kaho's ability to cast that card.
No other card is named in this ruling.
#2June 1, 2005· Wizards of the Coast
If another player gains control of Kaho, that player may cast any of the cards exiled with Kaho's ability.
No other card is named in this ruling.
#3June 1, 2005· Wizards of the Coast
Kaho's activated ability refers only to cards exiled by its triggered ability. If another effect exiled the cards, you won't be able to use Kaho to cast those cards.
No other card is named in this ruling.