not legal advice as usual.
Just for the record, the Divisional Court panel tasked by ONCA ( Ontario's Court of Appeal ) revisits several valuable statements describing the main principles of Ontario's Land Titles system :
Durrani v. Augier ( 2000 ) 22410 (ONSC ) https://canlii.ca/t/1w0x7 and
1168760 Ontario Inc. v. 6706037 Canada Inc. ( 2019) ONSC 4702 https://canlii.ca/t/j2b89
from Durrani 2000 (
criminal fraud by bogus documents )
" . . [40] The land titles system was established in Ontario in
1885, and was modeled on the English Land Transfer Act of 1875. It is currently known as the Land Titles Act, R.S.O. 1990, c. L.5. Most Canadian provinces have similar legislation.
[41] The essential purpose of land titles legislation is to provide the public with security of title and facility of transfer: Di Castri, Registration of Title to Land, vol. 2 looseleaf (Toronto: Carswell, 1987) at p. 17-32.
The notion of title registration establishes title by setting up a register and guaranteeing that a person named as the owner has perfect title, subject only to registered encumbrances and enumerated statutory exceptions.
[42]
The philosophy of a land titles system embodies three principles, namely,
the mirror principle, where the register is a perfect mirror of the state of title;
the curtain principle, which holds that a purchaser need not investigate the history of past dealings with the land, or search behind the title as depicted on the register; and
the insurance principle, where the state guarantees the accuracy of the register and compensates any person who suffers loss as the result of an inaccuracy.
These principles form the doctrine of indefeasibility of title and is the essence of the land titles system: Marcia Neave, "Indefeasibility of Title in the Canadian Context" (1976), 26 U.T.L.J. 173 at p. 174.
[42a] Indefeasibility of title has been defined as:
. . .
a convenient description of the immunity from attack by adverse claim to the land or interest in respect of which he is registered, which a registered proprietor enjoys. This conception is central in the system of registration. It does not involve the registered proprietor being protected against any claim whatsoever . . .
there are provisions by which the entry on which he relies may be cancelled or corrected, or he may be exposed to claims
in personam.
These are matters not to be overlooked when a total description of his rights is required.
But as registered proprietor, and while he remains such, no adverse claim (except as specifically admitted) may be brought against him. (Frazer v. Walker, [1967] 1 A.C. 569 (P.C.) at pp. 580-81.) . . . "

- unquote
from 1168760 Ontario ( 2019 ) " . . . 13 The LTA establishes the land titles regime in Ontario. Its essential purpose is to "provide the public with security of title and facility of transfer" by setting up a register and guaranteeing that the person shown as the registered owner is the legal owner, subject only to registered encumbrances and enumerated statutory exceptions.
14 There are three principles found in the land titles regime that together embody the doctrine of indefeasibility of title:
• The mirror principle, whereby the register is the perfect
mirror of the state of title;
• The curtain principle, which holds that the purchaser need not investigate past dealing with the land, or search behind the title as depicted in the register; and
• The insurance principle, whereby the state guarantees the accuracy of the register and compensates any person who suffers loss as the result of an inaccuracy. . . ." unquote